Timing of your Meals–Does it Matter?

by Yifan Xia

How would you feel if you were told to not have dinner for the rest of your life? Skipping dinner every day might sound shocking to most of us, but it was once a very common practice in ancient China in the Han Dynasty. In fact, even today Buddhism and Traditional Chinese Medicine (TCM) promote this practice as a healthier choice than eating three meals per day. But does this practice have roots in science? Of course, controversy exists around this topic, but one thing that we can be certain of today is that the timing of our meals can have a much greater impact on our health than we originally thought.

Researchers investigating the circadian system (internal biological clock) have started looking at the effects of mealtime on our health. Surprisingly, preliminary evidence seems to support the claims of Buddhism and TCM, indicating that eating meals earlier in the day might help promote weight loss and reduce the risk of chronic disease.

What are circadian rhythms and the circadian system?

Circadian rhythms are changes in the body that follow a roughly 24-hour cycle in response to external cues such as light and darkness. Our circadian system, or internal biological clock, drives circadian rhythms and prepares us to function according to a 24-hour daily cycle, both physically and mentally.

Why do they matter to our health?

Our internal biological clock is involved in almost every aspect of our daily lives: it influences our sleep-and-wake cycle, determines when we feel most energetic or calm, and when we want to eat.

These days people don’t always rely on their biological clocks to tell them when to eat, and there are many distractions in the environment that can influence mealtime. We typically think how many calories we eat—and what we eat—are the major contributors to our weight and health, but researchers have found that eating at inappropriate times can disrupt the internal biological clock, harm metabolism, and increase the risk of obesity and chronic disease.

What does the research say?

Although currently the body of research evidence for this area is relatively small, there are several human studies worth highlighting. One randomized, open-label, parallel-arm study, conducted by Jakubowicz, D., et al and published in 2013, compared effects of two isocaloric weight loss diets on 93 obese/overweight women with metabolic syndrome. After 12 weeks, the group with higher caloric intake during breakfast showed greater weight loss and waist circumference reduction, as well as significantly greater decrease in fasting glucose and insulin level, than the group with higher caloric intake during dinner. Another study published in the same year with 420 participants noted that a 20-week weight-loss treatment was significantly more effective for early lunch eaters than late lunch eaters. In 2015, a randomized, cross-over trial, conducted in 32 women and published in International Journal of Obesity, showed that late eating pattern resulted in a significant decrease in pre-meal resting-energy expenditure, lower pre-meal utilization of carbohydrates, and decreased glucose tolerance, confirming the differential effects of meal timing on metabolic health. However, few studies were identified reporting negative findings, probably due to the fact that this is an emerging field and more research is needed to establish a solid relationship.

 So when should we eat? Is there a perfect mealtime schedule for everyone?

“There are so many factors that influence which meal schedules may be suitable for an individual (including biological and environmental) that I cannot give a universal recommendation,” says Gregory Potter, a PhD candidate in the Leeds Institute for Genetics, Health and Therapeutics (LIGHT) laboratory at the University of Leeds in the United Kingdom and lead author on the lab’s recent paper reviewing evidence of nutrition and the circadian systems, published in The British Journal of Nutrition in 2016. Potter also comments that regular mealtime seems to be more important than sticking to the same schedule as everyone else: “There is evidence that consistent meal patterns are likely to be superior to variable ones and, with everything else kept constant, it does appear that consuming a higher proportion of daily energy intake earlier in the waking day may lead to a lower energy balance and therefore body mass.”

Aleix Ribas-Latre, a PhD candidate at the Center for Metabolic and Degenerative Diseases at the University of Texas Health Science Center and lead author on another review paper investigating the interdependence of nutrient metabolism and the circadian systems, published in Molecular Metabolism in 2016, also agrees: “To find the appropriate meal time has to be something totally personalized, although [it] should not present [too] much difference.” Aleix especially noted that people who are born with a tendency to rise late, eat late, and go to bed late (“night owls” versus “early birds”) are more likely to be at risk for metabolic disease.

Do we have to eat three meals a day?

How many meals do you usually have? In fact, how much food makes a meal and how much is a snack? There is no universal definition, which makes these difficult questions to answer.

“To maintain a healthy attitude towards food, I think it is important to avoid being too rigid with eating habits … I do think consistency is important as more variable eating patterns may have adverse effects on metabolism,” says Potter. “Although there is evidence that time-of-day-restricted feeding (where food availability is restricted to but a few hours each day) has many beneficial effects on health in other animals such as mice, it is as yet unclear if this is true in humans. I’d also add that periodic fasting (going for one 24 hour period each week without energy containing foods and drinks) can confer health benefits for many individuals,” Potter comments.

[See Hannah Meier’s recent article on intermittent fasting for more.]

Based on their research, Ribais-Latre and his lab have a different opinion. “We should eat something every 3-4 hours (without counting 8 hours at night). Many people complain about that but then consume a huge percentage of calories during lunch or even worse at night, because they are very hungry. Eating a healthy snack prevents us [from] eating too [many] calories at once.” He suggests what he considers a healthier mealtime schedule:

–          6:00 am  Breakfast (30% total calories)

–          9:30 am  Healthy snack (10%)

–          1:00 pm  Lunch (35%)

–          4:30 pm  Healthy snack (10%)

–          8:00 pm  Dinner (15%)

What if you are a shift worker or your work requires you to travel across time zones a lot? Ribais-Latre’s advice is “not to impair more their lifestyle… at least it would be great if they are able to do exercise, eat healthy, sleep a good amount of hours.”

What does Traditional Chinese Medicine say?

There are historical reasons behind the no-dinner practice in ancient China in the Han Dynasty. First, food was not always available. Second, electricity hadn’t been invented, so people usually rested after sunset and they didn’t need much energy at what we now consider “dinner time.”

However, there are also health reasons behind this practice. In TCM theory, our internal clock has an intimate relationship with our organs. Each organ has its “time” for optimal performance, and we can reap many health benefits by following this clock. For example, TCM considers 1:00 am – 3:00 am the time of “Liver”. The theory says that is when the body should be in deep sleep so that the liver can help to rid toxins from our body and make fresh blood. Disruption at this time, such as staying up until 2:00 am, might affect the liver’s ability to dispel toxins, leading to many health problems, according to the theory.

Many Western researchers do not seem to be familiar with the TCM theory. When asked about the practice of skipping dinner, Potter comments, “I think that skipping dinner can be a perfectly healthy practice in some circumstances; in others, however, it may be ill advised if, for example, the individual subsequently has difficulty achieving consolidated sleep.”

On the flip side, Ribais-Latre says that “skipping a meal is not good at all. We should not eat more calories than those we need to [live], and in addition, the quality of these calories should be high… If you can split those calories [to] 5 times a day instead of three, I think this is healthier.”

Even though there is no universal agreement on mealtime, the tradition of “skipping dinner” did come back into style several years ago in China as a healthier way of losing weight, and was quite popular among Chinese college women. Yan, a sophomore from Shanghai and a friend of mine, said that she tried the method for six months but is now back to the three-meal pattern. “The first couple of days were tough, but after that, it was much easier and I felt my body was cleaner and lighter… I did lose weight, but that’s not the main goal anymore… I got up early every day feeling energetic. Maybe it’s because I only ate some fruits in the afternoon, I usually felt sleepy early and went to bed early, which made it easier to get up early the next day with enough sleep… I’m eating three meals now, but only small portions at dinner, and I think I will continue this practice for my health.”

So what’s the take-away?

Mealtime does seem to matter. But exactly how, why, and what we can do to improve our health remains a mystery. Researchers are now looking into the concept of “chrono-nutritional therapy,” or using mealtime planning to help people with obesity or other chronic diseases. When we resolve this mystery, the question of “When do you eat?” will not just be small talk, but perhaps a key to better health.

Yifan Xia is a second-year student studying Nutrition Communication and Behavior Change. She loves reading, traveling, street dancing, trying out new restaurants with friends in Boston, and watching Japanese animations.



Can I Eat An Engineered Apple, Please?

by Delphine Van Roosebeke

The days of throwing your half-eaten apple away because it turned brown are over. Shiny non-browning apples are about to hit the consumer market in a few months. And this time, it’s not a fairy tale. Read on.

Cartoon from Pinterest

Cartoon from Pinterest

In 1812, the German Grimm Brothers created the shiny red apple in Snow White, featuring it as the symbol of evil given to Snow White by the witch on behalf of the jealous queen. The story was told to children to teach them not to trust strangers. Two hundred years later, it is the shiny green Arctic® Apple that brings people together to tell stories. This time, Okanagan Specialty Fruits Inc., a Canadian agriculture biotech company that creates new varieties of apples, has replaced the jealous queen. Don’t get me wrong, you won’t get poisoned as Snow White did, but you may be surprised by sliced apples that won’t brown for two weeks.

What are non-browning apples?

No matter how you slice, bruise or bite your apple, every apple turns brown eventually. When the apple’s flesh is cut, the oxygen in the air interacts with chemicals in the flesh of the apple. An enzyme called polyphenol oxidase, or PPO, makes melanin, an iron-containing compound that gives apple cells a brown tinge. The same type of ‘oxidative’ browning happens in the browning of tea, coffee and mushrooms. Within five minutes of slicing, browning can alter an apple’s taste and make it less aesthetically pleasing, but it doesn’t mean the apple is old or rotten.

To prevent this oxidative browning, Okanagan developed proprietary technologies to engineer genetically modified (GM) apples. The apples, called Arctic® Apples, produce reduced amounts of PPO. To achieve this, small gene fragments, called silencing RNAs, were injected into the apple seeds using bacteria. Such an insertion with gene fragments is a red flag for the apple cell, as it resembles the first step of viral attack. As a response, it chops up every sequence of DNA that looks like the suspicious fragment, and thus the PPO gene gets decimated. Because the PPO production is reduced to less than 10% compared to regular apples, the Arctic® Apple, even when sliced, will stay clear of browning for about two weeks. That’s roughly the same extended life span as apple slices from McDonald’s and Burger King, which use lemon juice and calcium ascorbate to prevent browning. Indeed, lemon juice and calcium ascorbate have a similar cosmetic effect to the silencing fragments inserted into the Arctic® Apples.

A regular apple, on the left, shows brown spots, while an Arctic® Apple has a clearer appearance. Photo by Okanagan Specialty Fruits

A regular apple, on the left, shows brown spots, while an Arctic® Apple has a clearer appearance. Photo by Okanagan Specialty Fruits

 Why do we need non-browning apples?

Is the world waiting for a non-browning apple or is this just another ‘we-can, so-we-do-it’ product that eventually may threaten the ecosystem or our bodies? Well, according to Okanagan, very few fresh-cut apples are available on fruit plates, in salads, in cafeterias, or on airplanes, primarily due to the browning issue. Anti-browning treatments are costly and often add an off-taste, the company says. But these treatments are not needed for Arctic® Apples, which is why Okanagan hopes to get their apples available in more places. Consumer research has suggested that apple products, such as bagged apple slices, are the number one produce item that customers would like to see more packaged versions of. Since apple slices are arguably easier to eat than whole fruits, this innovation could propel apple sales. Indeed, the simple convenience of baby carrots doubled carrot consumption, and Okanagan is endeavoring to achieve the same results with apples.

Another argument for bringing engineered non-browning apples to the consumer market is the reduction of food waste. According to the company, apples are among the most wasted foods on the planet, with around 30 to 40 percent of the apples produced never being consumed because of superficial bruising and browning. Given that 52 percent of fresh produce goes to waste in the U.S. alone, consumption of non-browning apples, such as the Artic® Apple, may be one small step in the right direction to shrink this enormous mountain of food waste.

When will you be able to eat them?
Cartoon from Pinterest

Cartoon from Pinterest

Non-browning apples have gotten the green light to get on the market, as both the USDA and FDA approved Arctic® Apples for consumption. According to Okanagan, the first commercial Arctic® Apple orchards were planted in 2015, but it takes a few years for newly-planted apple trees to produce much fruit. They expect small test market quantities from the 2016 harvest, followed by a gradual commercial launch starting in 2017 with increasing availability each year thereafter. The first two varieties that will be available to consumers will be the Arctic® Granny and the Arctic® Golden. Currently, Arctic® Fuji is next in line with others planned to follow!

Although Neil Carter, the president and founder of Okanagan Specialty Fruits, has expressed in the New York Times that the apples will be labeled as Arctic®, they will not explicitly label their apples as GMO. Unlike other genetically engineered crops, Arctic® Apples do not contain foreign DNA but silencing RNAs to reduce the expression of the PPO gene. Therefore, Arctic® Apples are not effectively captured by the current regulatory structure on GMO labeling. According to the company, the label Arctic® is sufficient to create transparency and let the consumers decide whether they want GM apples that don’t brown.

Food for thought on non-browning apples

Despite the millions of dollars and more than 20 years of research that went into the development of non-browning apples, not everyone welcomes the new shiny green Arctic® Apples from Canada. Since we already have hybrid ‘low browning’ varieties, such as the Cortland apple, and successful preservative treatments, some people wonder whether we really need a genetically engineered apple that doesn’t brown. In fact, with the advent of the non-browning apple, the food industry has departed from the premise that GM foods are meant to increase productivity. Indeed, the Arctic® Apple is one of the few GM products that is developed to improve the product cosmetically, to match the media-driven image of a perfect apple rather than improving the crop’s yield or nutritional performance. However, despite the maintenance of a fresher look, the preservability of non-browning apples is similar to conventional apples as Arctic® Apples will eventually still brown due to the rotting process by bacteria and fungi.

Given that PPO is involved in the plant’s defense mechanism, it has been speculated that the mutation in non-browning apples could make the plant more susceptible to insect and microbial pest damage, thus increasing farmers’ reliance on pesticides. Although more pesticides might be needed to maintain productivity of the crops, if non-browning apples actually do reduce food waste, growing fewer acres of non-browning apples may be adequate to meet the market demand. Also, the primary market of the Arctic® Apple is sliced apples, which is a subset of all apples consumed. However, as sliced non-browning apples find their way into more products, demand could increase from, say, parents wanting to use these apples as a convenient and healthy snack in their picky eater’s lunch box. This may eventually drive the need for increased production. Given these market dynamics, the cost-benefit of non-browning apples for the society is elusive and it remains to be seen to what extent the Arctic® Apple puts a burden on the natural environment.

Delphine Van Roosebeke is a rising Biochemical and Molecular Nutrition graduate with a background in biochemical engineering. When she is not thinking about dark Belgian chocolate, she’s eating it! Delphine has a crush on nutrients and the magic they perform in our body, and loves to share her knowledge with anyone who wants to hear it in a fun and approachable way! 



Lessons From the Anti-Fat Movement: Why Waging a War Against Sugar is Not the Answer

by Micaela Young

Blaming sugar for the obesity epidemic is tempting, but making it a target of public and policy concern may create unwarranted fear and an increased demand for sugar-free and sugar substitute products, steering us down an all too familiar—and perhaps even unhealthier—road.

Sugar Frankenstein JPG

It wasn’t too long ago that industry grabbed onto another contentious nutrition target during the anti-fat movement, profiting largely from a new host of fat-free and reduced-fat products, many of them packed with refined carbohydrates and sugar. In the 1980s, medical and nutrition science had not advanced enough to know that the link between total dietary fat and heart disease was far from clear. The first edition of the Dietary Guidelines for Americans in 1980 demonized fat and, as a consequence, sparked a wave of food industry innovation that grew to replace unwanted fats with refined carbohydrates and sugar. A probable catalyst for the U.S. obesity epidemic, this industry reformulation is a potential promoter of heart disease and diabetes, as suggested by several well-designed studies examining the consequences of a low-fat, highly-refined carbohydrate diet published over the last six years from top-tier journals: including the American Journal of Clinical Nutrition, Annals of Internal Medicine and Current Atherosclerosis Reports.

Earlier on, however, nutrition scientists had an inkling that not all dietary fat was created equal. Specifically, replacing trans fats and saturated fats with monounsatured and polyunsatured fats was more effective at reducing the risk of heart disease than reducing overall fat intake, as revealed in a 1997 study published in the New England Journal of Medicine. While there will always be debate and uncertainty, the health benefits of consuming certain dietary fats have gained a positive view in the scientific community, as reflected in the new 2015 Dietary Guidelines.

While this shift in thinking may be viewed as a gross misconception by the science community—having such a negative impact on public health—what is important to remember is that science is a dynamic, ever-revolving door. New evidence can change scientific thinking rapidly, calling important “facts” into question, but public opinion and consumer purchasing habits are much harder to change.

Today, history may be repeating itself, with a plethora of anti-sugar campaigns and policy movements following the flood of new research linking sugar consumption to obesity, diabetes prevalence, and heart disease. It turns out that sugar is a tricky beast to target, so public health advocates have gone after sugar-sweetened beverages. This is not a fool’s errand, however, because drinking your sugar seems to pile on the pounds, according to a randomized trial from the New England Journal of Medicine and a meta-analysis from the American Journal of Clinical Nutrition. In addition, added sugars are now thought to contribute to chronic disease risk and increased mortality, according to a 2015 study co-authored by Dr. Dariush Mozaffarian, dean of the Friedman School of Nutrition Science and Policy. Researchers estimated that sugar-sweetened beverages were responsible for 6,450 deaths from cancer, 45,000 deaths from cardiovascular disease, and 133,000 deaths from diabetes world-wide.

The public has caught on to this buzz around the negative effects of sugar consumption, and following suit are the usual suspects: the food industry (the wide-eyed consumer will notice new sugar-free and granulated sugar substitutes creeping onto grocery store shelves) and nutrition propaganda (anyone care to join me on Food Babe’s 7-day sugar detox?).

Policy makers have even jumped on the anti-sugar bandwagon, including former Mayor of New York City Michael Bloomberg, who in 2012 fought to ban the sale of sweetened drinks of more than 16 ounces. While Bloomberg’s proposal ended in a court decision denying his ban from going into effect, these types of efforts still continue.

Even though the concerns over added sugar consumption are warranted given current scientific consensus, the ambiguity around what these types of prohibitions on added sugars will do come from many factions: anti-hunger groups, scientists, and the soda-guzzling consumer who fears for his rights. One scientist against the banning and taxing of foods with high amounts of added sugars is Brian Wansink, the director of the Cornell University Food and Brand Lab, because he fears the unintended consequences. His reasons are just; in 2006, his lab conducted a study that linked low-fat labeled foods to misconceptions about the healthfulness of the products. On average, participants underestimated the calories in “low-fat” M&Ms and other foods by almost 50%, and, surprisingly, overweight individuals ate 60 more calories than normal-weight participants when presented with low-fat labeled foods.

In 2014, Wansink’s lab conducted a similar study on the implications of a soda tax after noticing more sugar-free foods on the market, and an increased effort to ban or tax sugar-sweetened beverages in certain locales. The results concluded consumers often made unhealthy substitutions for sodas. The main replacement? Beer and other high-calorie drinks. Not exactly the swap public health advocates were hoping for.

It is evident that something must be done to ease this public health concern, but the solution that will yield its intended results has not yet become apparent. The food industry uses current nutrition science to bring patchwork, processed foods to life, which can work monstrously against public health efforts. The important thing to remember is that, as stated in the 2015 Dietary Guidelines key recommendations, a healthy eating pattern limits added sugars (sorry, palm sugar) to 10% of calories per day—not including sugars from whole foods and fruits.

“It is clear that many Americans are consuming far too much sugar,” said Jeanne Goldberg, PhD, professor of nutrition and director of the graduate program in Nutrition Communication at the Friedman School. “But the best way to figure out if you are one of these people is to take a moment to figure out just how much you are getting, from your first bowl of frosted covered cereal in the morning to your last cup of tea. If this is over 12 teaspoons (about 50 grams) of added sugar—including the sugar in your frosted cupcake, not the sugar in your sugar snap peas—then you may need to cut back.”

Therefore, before we grab our torches and pitchforks and march toward Sugar’s house, let’s take a step back and think about the long-term implications of our well-intended actions. We would not want to steer the public towards an unhealthier eating pattern that, for example, includes more processed “sugar-free” foods with even more refined carbohydrates…

Micaela Young, CPT is a first year nutrition communication and behavior change student focusing in Agriculture, Food and Environment. She would trade you frosted cupcakes and breakfast cereal for chips and salsa any day.

Non-Chain Restaurants Tip the Scales

by Marissa Donovan

New research out of the Friedman School and the Human Nutrition Research Center on Aging (HNRCA) shows chain restaurants aren’t the only ones serving up excessive portions to diners.

While fast food and chain restaurants (defined as 20 or more locations) are often demonized for pumping out huge portions, it turns out they aren’t the only “bad guys.” Small, local restaurants pack a similar punch when it comes to calories served, according to a new study in the Journal of the American Academy of Nutrition and Dietetics.

William A. Masters, Ph. D, study co-author and professor of economics at the Friedman School of Nutrition Science and Policy, explains that although the issue of oversized restaurant portions has been apparent for some time now, it has never been formally studied. But now, there is a clear motivation to do so.

“With menu labeling comes the possibility of actually controlling portion sizes, so it’s finally worthwhile to measure and publish the data. Measuring something is a key first step towards improving it,” he said.

Researchers at Friedman as well as the HNRCA measured the calorie content of both chain and non-chain dinner entrées in 123 restaurants across Boston, San Francisco, and Little Rock, AR. The study focused on the most popular meals (with accompanying sides) from each of the restaurants, finding that a whopping 92 percent of meals, from chain and non-chain eateries, exceeded energy requirements for a single meal, which was benchmarked as 570 calories.

On average, a non-chain restaurant meal packed in 1,205 calories—more than half the daily requirement for women (2,000 calories) and almost half of men’s daily requirement (2,500 calories). In other words, based on these average calorie requirements, one restaurant meal was actually calorically equivalent to two full meals for average female diners (or 2.6 meals for women who need only 1,500 calories a day!).

What’s more? This striking number does not include appetizers, drinks, or dessert—which can contribute hundreds of additional calories. And the total calories in these non-chain restaurant meals were similar to the amounts measured in fast food and chain restaurants, which are commonly criticized for their role in promoting obesity.

Researchers measured dinner entrée calorie content in many different cuisines including American, Chinese, Greek, Indian, Italian, Japanese, Mexican, Thai, and Vietnamese. American, Italian and Chinese fare had the highest average energy density, reaching 1,495 calories per meal. Compared to American cuisine, Greek, Japanese, Vietnamese, Mexican, and Thai entrées delivered fewer calories.

There is sometimes a perception that smaller, local, mom-and-pop type restaurants are “healthier” than their well-known chain restaurant colleagues, but this study shows that this just isn’t true. It seems that eating out at restaurants in general promotes overeating, regardless of the ubiquity of the restaurant. The portions served at restaurants may even unintentionally inform portions at subsequent home-cooked meals, further exacerbating the problem.

While this study paints a grim picture for eating out, there are changes that can be made—both on a consumer level and policy level to combat this problem.

The researchers propose extending menu calorie labeling legislation to include all restaurants, not just large chains. As the rule stands, chain restaurants with 20 or more locations are required to provide calorie information on menus, with mandatory compliance by the end of 2016. While this legislation is great for diners at chain restaurants, it only affects about 50 percent of all restaurants/food outlets. Admittedly, enacting a regulation such as this at smaller restaurants is easier said than done.

“Like so many policy problems, there’s no one magic bullet. Making restaurant meals healthier will involve a lot of local steps, like municipal ordinances and state laws,” explained Masters. “There is also room for many voluntary steps by individuals, including food writers and restaurant reviewers as well as restaurants, groups and associations.”

Another idea proposed by the study authors is offering scaled down entrée choices at restaurants. Giving diners the option of half or third portions at adjusted prices would allow them to keep their portions in check before being tempted by a full plate of food. Until then, restaurant diners can take matters into their own hands and ask for half (or more) of their meal to be boxed to take home before they begin eating.

“Making the decision [to take half home] early gives power to your far-sighted self. The key is to make these decisions before you’re hungry, and especially before your appetite is revved up by an oversized dish,” said Masters.

Though, he admits that it’s very difficult to actually follow this advice, mainly because packing up and taking food home is such an awkward step.

“In practice, I think it’s much smarter just to choose menu items that will come in small enough sizes for you to be comfortable eating the whole thing. Use your far-sighted self to identify restaurants that offer delicious foods in portions suitable for your body size and activity level, then praise them for it on Yelp and Tripadvisor,” he said.

Don’t be fooled by the healthy façade of smaller, local restaurants—their dishes can also be calorie-laden. But you don’t have to give up dining out all together if you plan ahead and take steps to eat smaller portions.

Masters is confident that the problem of excessively large portion sizes can be solved.

“A first step is to realize that it is a problem, to measure what’s served and think carefully about what customers really want,” he said.

Marissa Donovan is a registered dietitian and second-year student in the MS Nutrition Communication & Behavior Change program with a focus in US Food and Nutrition Policy at Friedman. She loves hiking, traveling, finding new restaurants, and, of course, Netflix.

Should Athletes Juice It Up With Beetroot Juice?

by Katie Mark

Lettuce begin our workout at a higher beet. I’m not just talking about the new Beyoncé song, but the beetroot that comes from the beet plant. Beet it with the juicing cleanses, and juice up your water with beetroot (BR) juice.

The beetroot and dietary nitrates

The beetroot vegetable is the taproot part of a beet plant. It is a rich source of dietary inorganic nitrates that serve as the active ingredient to the health benefits. Once consumed, the nitrates mix with bacteria in our saliva to be converted into nitrites. Traveling to the stomach, some of the nitrite converts to nitric oxide (NO). The nitrite that is not converted is then circulated and stored in our blood. Nitrites can convert to NO during low oxygen availability, which usually occurs during exercise in skeletal muscle.

NO is a commonly occurring compound in the body, and BR juice adds to these levels. NO dilates blood vessels and improves blood flow to lower blood pressure.

What are the purported benefits of beetroot juice?

Scientists have exercised their love of beetroot juice in various experiments. In numerous small studies containing mostly men and high-level athletes, those consuming BR juice experienced slightly enhanced performance.

Benefits of BR juice include:

  • Lowering blood pressure
  • Enhancing exercise capacity, in certain situations
  • Lowering the amount of O2 your muscles need for submaximal and maximal exercise
  • Delaying the decline in cognitive function
  • Fighting inflammation
  • Detoxification
  • Providing nutrients and fiber

Beetroot juice and sport performance: What the science says

BR juice acts as an ergogenic aid, which is any substance that enhances athletic performance. Due to the production of NO, BR juice reduces the oxygen cost of exercise, lowers blood pressure, and keeps an athlete focused during exercise. Let’s take a look at some studies.

A double-blind, placebo-controlled, crossover study published in the Journal of Applied Physiology used eight healthy men to evaluate the effects of BR juice on blood pressure and the oxygen cost of exercise. The men had 500 ml/day of BR juice or placebo for 6 consecutive days. Moderate- and high-intensity exercise tests were completed on the final 3 days. They found that systolic blood pressured decreased by about 8 mmHg. The time to exhaustion increased by 16% with BR juice supplementation.

A double-blind, randomized, crossover study recently published in the European Journal of Applied Physiology used 16 male athletes (rugby, hockey and football players) to drink BR juice for 7 days. On day 7, all participants completed an intermittent sprint test. They were also given cognitive tasks designed to test how accurately and how fast they made decisions. Each participant completed these tasks after taking a nitrate-rich beetroot juice shot (400 mg of nitrates per shot) and a placebo version with the nitrate removed. Researchers found that the nitrate-rich version saw an improvement in both sprint performance (3.5%) and speed of making decisions (3%) without negatively affecting decision accuracy.

Another double-blind, randomized crossover study explored BR juice and its effects on muscle efficiency and intense intermittent (stop and go) exercise. Fourteen male athletes drank 490 mL of nitrate-rich BR juice and nitrate-depleted placebo juice over 30 hours before an intermittent recovery test. Performance was 4.2% better with BR juice. The nitrite concentration decreased by 20% with the placebo compared to 54% with the BR juice. The researchers suggested that nitrate supplementation could promote nitric oxide production and improve performance, which may be due to muscles being able to take up more glucose or better maintenance of exciting muscles during contraction.

Limitations: These results demonstrate tiny improvements in people who are already trained. However, these small improvements may actually be important for competitive athletes for which a few minutes can make or break winning a race or beating their own time on a time trial. Preventing the decline in decision-making is important for team sports like soccer and football. Continue on to evaluate if you’re an athlete who could benefit from BR juice.

Are you an athlete who could benefit from BR juice?

Just because you’re an athlete or you workout everyday doesn’t mean that BR juice is the drink for you. Intensity and duration of the sport as well as the fitness of the athlete is critical to evaluating whether or not it is ergogenic for the athlete.

Nitrates could affect athletes who do more stop and go exercise (i.e., sprints, high-intensity interval training, etc.) seen in team sports. Those who are endurance athletes may not benefit as much. Yet, the effect of BR juice on prolonged endurance exercise has not been studied as much.

Also, in low-intensity endurance exercise, the muscles are usually sufficiently oxygenated that there is little need for nitric oxide to help increase blood flow and oxygenate our muscles more.

Deets on Beets


The range of nitrate intake for the health benefits is 300-600 mL. For instance, Beet-It makes concentrated BR juice in 70 mL shots, which is about 300 mL of beet juice. The concentration is to help avoid digestive problems that may arise. Some athletes use around 500 mL of BR, or two shots. However, a higher intake of nitrates does not translate to better sport performance.


An acute (2-3 hours before exercise) or a short-term (at least 3 days) protocol can be used. Short-term strategies can help the performance of high-intensity exercise (taken a few days before). Acute supplementation and sport performance lacks consistent results because of differences in health, diet, age, fitness and sport of the athlete. However, it can still be taken 2-3 hours before exercise.


  • Red stool and urine. The carotene in beets give it that beautiful color, but as the carotenes travel through the gut unabsorbed they may end up adding a red hue to the stool and urine. This discoloration is harmless. Just be prepared!
  • Upset stomach, diarrhea, and nausea. Some people may experience upset stomach, diarrhea and nausea. This is why BR juice manufacturers concentrate their shots of BR juice.
  • Dietary oxalates. It is suggested that those with kidney stones should avoid BR juice because it contains oxalates. If you currently have or have a history of kidney stones then speak to a registered dietitian. There’s a bit of conflicting research on which foods increase formation of kidney stones in at-risk people.

Beetroot juice or the entire beetroot: Does it matter? 

The roots of the beetroot are usually eaten boiled, roasted or raw. They can either be eaten alone or with any salad vegetable.

Research from the Journal of the Academy of Nutrition and Dietetics investigated if eating beetroot could improve endurance exercise performance in 11 fit men and women. All participants ate baked beetroot (200 g containing >500 mg nitrate) before a 5-km time trial on a treadmill. In a separate trial, each participant had cranberry relish (as the placebo) before the time trial. The study found that the average running speed was faster after eating beetroot. There was a 5% increase in speed during the last 1.1 miles of the run. It was concluded that eating beetroot ~60 minutes before exercise may improve running performance in healthy adults.

If you decide to take BR juice powder, be sure to follow the manufacturer’s directions, especially the timing. Most powders require intake ~30-60 minutes before exercise since they’re concentrated shots. One-teaspoon of BR powder is about three beets.

Beetroot juice is promising

BR juice demonstrates that there’s a performance benefit from eating vegetables. These benefits may usher in either a few days leading up to exercise (if you’re “nitrate loading”) or 2-3 hours before exercise (acute supplementation). BR juice lowers blood pressure and may improve sprint performance and mitigate the decline in decision-making that can occur in some sports. Whole BRs are a good alternative to concentrated “shots” of BR juice (if you’re trying to save money or want to take advantage of beets in your recipes).

The great thing about BR juice is that it doesn’t come in a man-made pill to help sport performance. It’s actually food. So try a BR juice shot before your next intense training session or competition. With BR juice, you can’t beet unleashing the power of food.

Katie Mark is a second year MS/MPH student and avid road cyclist. She will ride 100 miles for the Best Buddies Challenge in May and 185 miles over two days for the Pan-Mass Challenge in August. She will take shots of beetroot juice before both rides.


Nutrition and Diabetes: A Closer Look at Current Research

by Katelyn Castro

No one ever said understanding the components of a healthy diet would be simple. The connections between nutrition and disease continue to grow and evolve as scientific research emerges. Consider the most recent publication of the 2015 Dietary Guidelines for Americans (DGA). All of the past and present dietary guidelines may share some common themes, but every five years they are updated after an extensive review of the current scientific literature.

Similar to the process of the DGA, the American Diabetes Association (ADA) systematically reviews the latest research on diabetes care and releases new guidelines including specific nutrition recommendations. As the science on the role of nutrition in the pathophysiology of diabetes advances, the ADA’s most recent report, Standards of Medical Care in Diabetes—2016 aims to put the current research in perspective. Before getting into the recommendations, understanding the basic science of diabetes is crucial.

The Science Behind Diabetes

Diabetes Mellitus, more commonly known as diabetes, makes up a large group of endocrine disorders (See “Is There a Fourth Type of Diabetes?” and “Debunking 6 Myths About Diabetes“). But, for the purpose of this article, we will focus on type 1 and type 2 diabetes. While these two types of diabetes differ in etiology, they share a common characteristic: high blood glucose (hyperglycemia), caused by a defect in insulin production, insulin action, or both.

Insulin is an important hormone, produced and secreted by the beta cells in the pancreas. One of its major functions is to keep blood glucose levels within a healthy range, by working closely with another hormone, glucagon. For people without diabetes, fasting blood glucose typically ranges from 70 to 100 mg/dL.

After eating a meal, glucose and amino acid levels in the blood rise, signaling the pancreas to release insulin. Insulin allows glucose to be transported out of the blood and into liver, muscle, and fat cells for immediate energy or for stored energy as glycogen and fat.

On the other hand, after exercise or between meals, glucose and insulin levels drop, causing another hormone, glucagon to be released. Glucagon signals the liver to convert glycogen back into to glucose to raise blood glucose levels. If glycogen stores are exhausted, glucagon can also signal the liver to make new glucose from amino acids, usually from muscle protein. By working together, insulin and glucagon keep blood glucose levels within a relatively narrow range, while making sure our brain, muscles, and other organs get the energy they need to function properly.

Unfortunately, this is not the case for people with diabetes. Type 1 diabetes is an autoimmune disease where the beta cells in the pancreas are destroyed so the pancreas cannot produce adequate insulin.

In type 2 diabetes, the body cannot use insulin effectively because muscle, fat, and liver cells become resistant. At first, the pancreas tries to overcome insulin resistance by producing extra insulin to help glucose get into cells. But eventually, the pancreas can’t keep up with the high need for insulin and loses the ability to produce it. While type 2 diabetes can be reversed in the early stages, late-stage type 2 diabetes must be handled similarly to type 1 diabetes: with insulin medication. Balancing insulin doses effectively with diet is the key to managing abnormal blood glucose levels, the cause of many of the serious diabetes-related health concerns.

For instance, if people with diabetes take too much insulin, blood glucose levels can drop extremely low, causing seizures, loss of consciousness, and even death. On the other hand, if people with diabetes don’t take enough insulin when eating, blood glucose can rise very high, causing headaches, blurred vision, and fatigue. Also, when extremely high blood glucose levels are not treated quickly, diabetic ketoacidosis can occur and cause shortness of breath, vomiting, or a coma.

Untreated hyperglycemia can also contribute to many long-term complications, such as cardiovascular disease, kidney damage, nerve damage (neuropathy), and blindness. Several studies have found that long-term hyperglycemia accelerates the formation of advanced glycation end products (AGEs). A recent study suggests that AGEs are mediators of many diabetes complications because they speed up oxidative damage and increase inflammation, which are linked to many of the health conditions listed above. Given these serious health consequences, management of abnormal blood glucose levels is one of the primary goals of diabetes care.

Nutrition and Diabetes Management: The Consensus from Current Research

According to the Standards of Medical Care in Diabetes—2016, nutrition therapy plays an integral role in overall diabetes management. Within this report, the American Diabetes Association conducted a systematic review of all available research on diabetes nutrition research, using a strict grading system according to the level of evidence:

A: Clear evidence from a well-conducted randomized controlled trial or Evidence-Based Medicine at the University of Oxford

B: Supportive evidence was from well-conducted cohort studies

C: Supportive evidence was from poorly controlled or uncontrolled studies or conflicting evidence with weight of evidence supporting recommendation

E: Evidence was from expert consensus or clinical experience

Together, the ADA states that the recommendations in the report aim to help people with diabetes reach individualized glycemic, blood pressure, and lipid goals; achieve a healthy body weight; and delay and prevent complications of diabetes. The following paragraphs are a review of some of the recommendations in the 2016 report.

Carbohydrates remained a hot topic, consistent with earlier ADA reports. The ADA recognizes that the amount of carbohydrates and available insulin are important factors influencing glycemic response (blood glucose control). The report recommends that certain people with type 2 diabetes who are not taking insulin may benefit most from education that emphasizes healthy food choices and portion control (B rating).

In contrast, carbohydrate counting or estimation to determine insulin at mealtimes is recommended for people with type 1 and 2 diabetes who use fixed insulin therapy to improve glycemic control (A rating). These recommendations are consistent with previous research, finding that carbohydrates cause an immediate and significant increase in blood glucose, while protein has a much smaller effect, and fat has the least impact. In addition, studies have found that adding protein or fat to a carbohydrate meal slows the blood glucose response and lowers blood glucose levels, when compared to the response of a carbohydrate-only meal.

The new report also emphasizes the quality of carbohydrates more than the quantity of carbohydrates. While previous reports have listed a minimum amount of carbohydrates and specific recommendations for grams of fiber, the 2016 ADA recommendations focus on identifying healthy sources of carbohydrates. To avoid displacing nutrient-dense foods, carbohydrates from vegetables, fruits, whole grains, legumes and dairy are recommended, especially high-fiber and low glycemic load foods (B rating). More specifically, the 2016 report recommends that all people with diabetes avoid sugar-sweetened beverages to control weight and lower risk of CVD and fatty liver (B rating), which is stricter than previously reports that only recommended limiting sugar-sweetened beverages. Similar to carbohydrates, fat quality is highlighted rather than quantity in the report. Specifically, omega-3 fatty acids are recommended to prevent or treat cardiovascular disease.

While evidence on the ideal amount of carbohydrates, fat, or protein remains inconclusive (E rating), a healthy eating pattern with calorie reduction continues to be recommended for overweight adults with type 2 diabetes to support modest weight loss (A rating). In addition, the ADA states that a Mediterranean diet, low in carbohydrates and rich in monounsaturated fatty acids, is considered as effective as the traditionally recommended low-fat, high-carbohydrate diet for glycemic control and cardiovascular improvements (B rating). Although some research studies advocate for carbohydrate restriction as the primary approach in diabetes management, as outlined in this critical review, the ADA is not completely on board. To meet the ADA evidence-based criteria for nutrition recommendations, long-term randomized controlled trials are needed to address concerns about the efficacy and safety of a restricted carbohydrate diet for diabetes management.

The report also addresses restrictions on alcohol intake (C rating), which are the same as those recommended for the general population. In addition, recommendations for sodium restriction are consistent with previous reports and that of the general population (less than 2,300 mg/day), although a stricter restriction is recommended for people who have both diabetes and hypertension (B rating). Despite this comprehensive review of current evidence from diabetes nutrition research, the ADA makes an important point: the evidence is only one component of decision-making.

The Role of the RD and the Individual

After understanding the research supporting various nutrition recommendations, registered dietitians are responsible for working with people with diabetes to translate the population-based research into practical terms for individuals. As the ADA recognizes in the report, the research does not identify a one-size-fits-all eating pattern for people with diabetes. Instead, people with diabetes should follow an eating plan most appropriate for them by taking into account personal and cultural preferences, health literacy and numeracy, and willingness and ability to make behavior changes. This individualized approach can help people with diabetes maintain the pleasure of eating, while also meeting personal health goals through education and counseling on evidence-based recommendations.

For example, consider nutrition recommendations for a 40-year-old woman who is part of a traditional Asian family and has type 2 diabetes. While replacing white rice with brown rice in her diet may be an unrealistic goal because of her family’s cultural values, choosing fresh fruit instead of fried ice-cream for dessert may be more manageable for her. Now, consider recommendations for a 16-year-old teen recently diagnosed with type 2 diabetes. Teaching him about portion control and how to identify high- and low-carbohydrate foods may be simpler and more feasible than explaining carbohydrate counting initially.

Nutrition, Diabetes, and the Big Picture

Taking a larger socio-ecological perspective on the role nutrition in diabetes is equally important as scaling down recommendations for individuals with diabetes. While nutrition plays a critical role in management of diabetes, many other factors also impact health and wellbeing: physical activity, smoking status, social support, stress, sleep, and mental health.

Just as no single eating pattern has been found to be most effective for all people with diabetes, no one component of diabetes management should be underscored without addressing other important sectors of health. By taking the current research on diabetes nutrition into perspective, people with diabetes can find an eating pattern that is both consistent with research and in line with their personal values and health goals.

Katelyn Castro is a first-year student in the DI/MS Nutrition Program at the Friedman School. She is passionate about teaching nutrition to kids and has spent the past two summers working with kids with type 1 diabetes at the Barton Center.

Aqua… Advantage?

by Alexandra Simas

Fish are a fabulous source of many nutrients, including omega-3 fatty acids. Growing popular demand has strained the limits of commercial fishing. Farmed fish help meet the growing need, but this system still has a significant environmental impact. Working towards the goal of increasing aquaculture efficiency, Massachusetts-based AquaBounty has created the AquaAdvantage® salmon, the first genetically-modified (GM) animal approved by the FDA for sale and consumption.

What makes AquaAdvantage® salmon different?

These GM salmon grow rapidly and reach consumption size far faster than their non-GM Atlantic salmon counterparts. This increased growth is a result of inserting a modified Chinook salmon growth hormone gene, which produces a protein very similar to the Atlantic salmon’s orthologous protein, into the Atlantic salmon.


A GMO salmon in the background compared to non-GMO salmon in foreground.  From AquaBounty

The key difference lies in the promotor, which controls timing and quantity of growth hormone production. The endogenous salmon promotor regulates growth in a seasonal manner i.e. the salmon grow more when the environment is conducive to growth. Conversely, the Chinook gene is inserted along with a promoter from an eel, the ocean pout. In the pout this promoter regulates the production of an antifreeze protein. Since this protein prevents the eel from freezing in its sub-zero natural habitat, it’s important to produce it at constant levels every day of the year. AquaBounty takes advantage of this perpetual green light to ensure their GM salmon are pumped full of growth hormone every day of the year.

The increased growth means AquaAdvantage® salmon are full-grown within 18 months rather than 2 years for conventional farmed salmon or 3 for wild, allowing greater food production and/or reducing environmental impact.

Next step, take over the world?

A common concern with genetically modified organisms is their interaction with the environment and native species. AquaBounty is confident its precautions will prevent their salmon from escaping to natural salmon habitats, by growing salmon in tanks on land (though this does not mean the tanks can’t be near rivers or lakes). In the case that their salmon do reach the ocean, all salmon raised will be both female and sterile.

The sterility is achieved by making the fish triploid. This means they possess two copies of each maternal chromosome and one copy of each paternal, for a total of three copies of each. Fish, like humans, are naturally diploid, possessing only one copy of each chromosome from each parent. Triploid animals do occur rarely in nature, but are usually sterile. Producing female, triploid fish populations via temperature shocks, high pressures, or chemical treatments is already an established practice (with 99% accuracy), employed by companies such as Troutlodge to supply “trophy trout” for sport fishing with minimal impact on native populations. A key point here is that a small population of diploid i.e. fertile salmon must always be raised to breed the next generation.

One concern about GM organisms is that they may be more fit than their conventional counterparts, giving them an unfair advantage if they escape containment. In a review published earlier this year, Robert H. Devlin, a research scientist with Fisheries and Oceans Canada, headed a team that sought to elucidate the potential environmental impact of escaped GM salmon. They did this by reviewing over eighty studies on fish genetically modified through the addition of growth hormone transgenes. They concluded that GM fish are usually created from strains closely related to their wild counterparts, and therefore are quite capable of interbreeding should fertile fish escape. However, the differences between GM and wild fish do not necessarily confer advantage. The increased growth comes at the cost of other functions, such as immune function and swimming ability.

On the other hand, Fredrik Sundström, an ecologist at Uppsala University in Sweden and another author on this study, contends that “it’s very difficult to predict any ecological consequences before these fish are actually in nature, when it’s kind of too late to do anything about it.” Will they dominate due to their size, or will their phenotypic tradeoffs ensure they die off without having much impact on the native ecosystem?

Like all livestock, farmed fish are more prone to disease and infection because of their close living quarters. Any farmed fish escapees spread pathogens among the wild population. If GM salmon escape and outcompete wild-type salmon due to their large size, they could spread the pathogens more widely. Furthermore, even if the escapees are sterile, the competition could effectively reduce the wild population by starving out the wild salmon.

Are GM salmon more likely to cause allergies?

Fish is a common allergenic food, and genetic modification can affect protein production. Could AquaAdvantage® salmon be more allergenic than other salmon? The FDA found that AquaAdvantage® triploid allergenicity was no different from non-GM, wild caught salmon. However, caveats include a sample size of just six fish per group, and that only wild caught salmon were used as controls, in contrast to many of the other tests performed, such as fatty acid profile, where farmed salmon were included. Since these salmon are farmed, farmed salmon are a better control. Returning to the breeding diploid population mentioned above, GM diploid salmon possessed higher allergenic potency in one test, while other tests performed were flawed and could not be used according to the FDA. They concluded that “insufficient data and information were available from which to draw a conclusion regarding possible additional allergenic risk posed by diploid [GM] salmon.”

How do I know if I’m eating GM salmon?

You wouldn’t unless the vendor volunteers that information, since there are no laws requiring labelling of GM foods. But what vendor is going to choose to tell you?

No matter how thorough testing of new products is, innovation is always accompanied by a certain amount of risk in the unknown. History is filled with novel policies or inventions, like DDT and Agent Orange, chlorofluorocarbons, or BPA, that seemed wonderful at the time, and based on the cutting edge scientific research of that day they were deemed safe. But as new scientific knowledge was discovered they were found to be extremely harmful. The thing is, we can only test and look for markers or effects we already know exist. Additionally, as time passes studies with longer time points can be performed by independent bodies.

Genetically modified products may prove to be completely harmless in the long run, but we don’t know what the future will hold. The FDA has determined that since the GM salmon are not materially different from their conventional counterparts (they may be bigger, but they have the same nutrient profile) they don’t require labelling. But what if tomorrow a researcher discovers a new marker that is biologically relevant to those consuming it and is substantially different between GM and conventional?

In the meantime, many groups are demanding mandatory labeling. Mandatory labelling would not prevent the sale or purchase of the GM products. While some consumers without strong opinions might gravitate towards a non-GM product if offered a choice between the two, thus reducing sales of GM products, the fact that a company would sell more product if they didn’t have to give consumers more information about it hardly seems a compelling reason to not require labelling. Mandatory labelling wouldn’t harm any consumers, and it would only help consumers make better decisions.

The bottom line:

Genetic modification has incredible potential to improve our lives, diets, and environment. However, we still have much to learn about the biological effects of both genetic modification and traditional breeding, and a lack of evidence against something is not necessarily equivalent to evidence in favor of something. In the case of AquaAdvantage® salmon, my primary desire is, as usual, to see more independent studies with longer-term outcomes (and sample sizes greater than six!). Beyond that, my major concerns at this point are more about the effects of farming on things like nutrient profile and pollutant levels than about their genetic modification, though due to their reduced immune function, I would be even more concerned about the rates of antibiotic usage on GM salmon than conventionally farmed salmon.

Alexandra Simas is a second-year PhD student in Biochemical and Molecular Nutrition.