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.

aquavantage-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.

Is There a Fourth Type of Diabetes?

by Shannon Dubois

We all know about diabetes: the infamous enemy of our bodies’ blood glucose homeostasis; the delicate balancing act between insulin and glucagon to keep our blood sugar stable. Type 1 and type 2 diabetes are the most well-known and talked about, type 3 was brought to the table a few years ago, and type 4 has just been “discovered.” So, what is this newest type of diabetes, and should we be worried?

As a reminder, type 1 diabetes is the insulin-dependent form of diabetes mellitus where pancreatic beta cells (typically destroyed by an autoimmune response) do not supply insulin to the body to signal cellular glucose uptake, resulting in high blood sugar.

Type 2 diabetes mellitus is primarily caused by insulin resistance (cells becoming desensitized to insulin’s action due to overuse), and decreased insulin production over time as the pancreas gets “worn out” from overproduction. This type of diabetes is often associated with obesity, inactivity, and aging.

The less talked about, newly termed (by some) type 3 diabetes is discussed in a 2008 literature review and is proposed to be linked to insulin deficiency and insulin resistance in the brain as contributors to Alzheimer’s Disease neurodegeneration, thus a sort of combination of type 1 and 2 that can lead to cognitive decline.

Now to the latest discovery: a fourth type of diabetes to keep on our radar. An article published around mid-November in Nature detailed the results of a study led by Salk Institute researchers who were investigating age-associated insulin resistance. They discuss how obesity-associated insulin resistance (driven by inflammation due to macrophages), which is deemed to be a large contributor to type 2 diabetes, is different from age-associated insulin resistance, which occurs independent of obesity.

The authors explain that “fat-resident regulatory T cells, termed fTreg cells, accumulate in adipose tissue as a function of age, but not obesity.” These cells lead to the age-associated insulin resistance that the article discusses. Thus, it seems that no one is safe from this disease—even the lean and physically active healthy eaters can fall prey to type 4 diabetes as a simple consequence of aging.

The article concludes that fTreg cells are implicated as potential therapeutic targets for treating age-associated insulin resistance, suggesting that fTreg cells could be depleted to increase insulin sensitivity and, therefore, ameliorate diabetes symptoms.

Overall, it doesn’t seem that this is a newly discovered type of diabetes per se, because it has long been known that even lean people are sometimes diagnosed with diabetes. Whether it was believed to be due to a genetic predisposition, or just attributed to the process of aging, it seems that this article is more the discovery of a mechanism that may be at play than of the condition itself.

The authors suggest “type 4 diabetes as a designation for non-obese-dependent fTreg-driven metabolic disease of the elderly,” and this may be an appropriate designation for the mice they have studied, but maybe not to classify humans just yet. This study did only include mice, so their findings would have to be proven in humans as a next step. Keep an eye out for future research on this topic, as it is hopefully coming soon.

Shannon Dubois is a second-year Master’s student studying Biochemical and Molecular Nutrition.

Edible Seaweed: An Ancient Vegetable from the Sea

by Nusheen Orandi

We call it an exotic “health food” now, but edible seaweed became part of the world’s cuisine thousands of years ago and still remains a normal kitchen ingredient in many parts of the world. Why should we pay more attention to the stuff that gets stuck in between our toes at the beach? While western chefs and foodies play catch-up to the rest of the world by switching up their vegetable dishes, nutrition scientists say seaweed offers health benefits. Perhaps both contribute to why U.S markets are starting to make room for this sea vegetable on grocery shelves.

The health benefits of edible seaweed

Edible seaweed can be a good source of vitamins, minerals, and other nutrients and hosts many health benefits that can add value to our diets. The nutrient content of seaweed can depend on the variety. People harvest green, red, and brown seaweed in Japan, China, Korea, the Philippines, India, New Zealand, and many other parts of the world. There are over 30 commonly eaten seaweeds.

Seaweed is rich in complex carbohydrates and protein, with red seaweed containing the most protein. Seaweed also contains omega-3-fatty acids, which have been shown to promote heart health by lowering triglyceride levels (bad fat) in the blood. Seaweed is comprised of fiber as well. About a ¼ cup serving of fresh seaweed, or a couple tablespoons of dried seaweed (like nori), has approximately one gram of fiber.

As an antioxidant-rich vegetable, seaweed provides us with some of the immune-boosting vitamins such as vitamin A, C, and E. A single serving of seaweed (about two tablespoons) also gives about a fifth of the daily recommended amount of vitamin K, which plays an important blood clotting role in the body and helps maintain bone health. But, it is the vitamin B12 in seaweed that may really pack a nutritional punch. Dr. Jeffrey Blumberg, director of the Antioxidant Laboratory at the USDA’s Human Nutrition Center on Aging at Tufts University, explained why: “It’s not just important to look at the nutrients present in a food, but how readily those nutrients are released once you eat it.”

The healthfulness of a food depends on how much of a nutrient is released once we eat it (its bioaccessibility) and how much of that nutrient our body can take up (its bioavailability). So, nutrients in a food are only useful if the body can take them up in the first place. This makes seaweed curious because most plants do not contain bioavailable vitamin B12. Research conflicts with whether the vitamin B12 in seaweed really is bioavailable or not. For example, it has been shown to be bioavailable in the red seaweed known as purple laver, which is usually sold dried. But it is not clear if other edible seaweeds have bioavailable sources of vitamin B12. However, this potential source could benefit people trying to include more plants in their diet. It would also suit vegetarians, who usually have few food sources of vitamin B12. Animal foods, such as red meat, act as the main source of vitamin B12, however nutrition professionals recommend that most healthy diets should consist of less red meat.

What gives seaweed its high mineral content? Some scientists suspect it is the exposure to ocean minerals. Seaweed has plenty of minerals like calcium, potassium, magnesium, iron, iodine, zinc, selenium, and copper, which have diverse functions in the body. A single serving of seaweed (particularly green or brown seaweed) provides over half of the daily-recommended amount of calcium. In fact, the calcium found in seaweed (calcium phosphate) is more bioavailable and useful to our body than the calcium found in milk (calcium carbonate). Seaweed is a major source of iodine. Brown seaweed contains the most iodine, while green and red seaweed contain less. The other primary source of iodine is iodized salt. But, as Dr. Blumberg noted, “If people are being told to decrease salt intake in their diet, then that means that they are also taking in less iodine in their diets.” This especially applies to heart patients on low-salt diets that may be at risk of iodine deficiency.

The health risks of edible seaweed

Seaweed can pose risks for some people. For example, people with thyroid health problems would do best to avoid large amounts of brown algae because of its high iodine content. A person with kidney problems could also be at risk because red seaweed, such as dulse, is very high in potassium and could present a risk of potassium toxicity.

What makes seaweed any better than the usual green veggies, like broccoli and lettuce? It’s not so much that it’s superior to other vegetables, but that it can add variety to a healthy diet that, as Dr. Blumberg said, should lean in a plant-based direction.

“I would argue that one of the things we need people to do is to eat more plant food. And, that can be done with one of the principles of nutrition: diversity of the diet. A healthful food doesn’t have to be a ‘superfood,’ just a good, nutrient-dense food,” he said.

So edible seaweed is full of good things. But, how are we supposed to eat this mildewy-looking green stuff? Cooking with seaweed may seem like a high dive, but you can actually easily work it into any meal or snack.

Cooking with edible algae

You don’t need to learn how to roll sushi in order to cook with seaweed. Different types of seaweed, fresh or dried, add unique flavors to soups, meats, salads, and snacks.

Kelp is a popular form of seaweed, usually dried, that people cook with. Kombu, a brown kelp, is one of the most common types. It comes in dried sheets in most grocery stores. You can rehydrate it by adding water to be used in salad, stir fries, or with fish. You can even add it dried to soups or rice dishes for flavor. As it gets cold out there, try out this Seared Salmon with Winter Vegetables and Kombu Broth recipe.

Did you know you could add a vegetable to your popcorn? Well, with red seaweed, you can! Dulse, red seaweed, is sold in the form of dried flakes, which gives it the nickname “sea lettuce flakes.” It has a naturally salty flavor and chewiness that dresses up your popcorn nicely. Just add about ¼ cup of dulse flakes to your favorite bag of popcorn kernels, and let it pop!

If you try a seaweed salad in a Japanese restaurant, its main ingredient is probably wakame. You buy wakame dried, but once you add water to it, it turns into a dark green and slightly crunchy vegetable. Cucumbers and sesame seeds complement wakame in a salad, such as this easy Sunomono (Cucumber Salad) recipe.

The most well known seaweed is probably nori, a dark green seaweed. It’s often seen as sushi’s belt and adds a salty and vinegar flavor to seafood. You find nori as dried sheets, just like kombu. You can break it up and add it to your trail mix, or cut it up into strips and use it as a healthy cracker substitute for an appetizer. Get fancy with this Tuna Tartare and Nori Chips recipe.

Arame is a funky, dark brown kelp that comes in dried, long strands. It actually tastes slightly sweeter than other kelps and adds flavor to an assortment of dishes. Arame brings a blend of texture to a dish, such as in this Arame and Edamame Salad, where you get creamy and crunchy all in one bite.

Remember when trendy kale chips swept through Whole Foods? Seaweed chips naturally have lots of flavor and also provide a healthy alternative to even our guiltiest snack cravings. Roast 3-4 cups of seaweed with a teaspoon each of salt and pepper and a dash of lemon juice.

If the vegetable drawer of your refrigerator tires you out, adding this flexible and flavorful sea vegetable to your meals could benefit both your health and your palate.

Nusheen Orandi is a second-year student from California in the Nutrition Communication program with a concentration in Agriculture, Food and Environment. She likes to spend her time tea-shop hunting, breakfasting, tensely watching the Tottenham Hotspurs, and cooking and eating with friends and family.

The GMO Debate: A Case of False Dichotomies

by Hannah Packman

The use of genetic modification in our food system is a polarizing issue. However, the current discourse often ignores the grey areas, and may be detrimental to the public understanding of GMOs.

The ability and willingness to admit mistakes is often considered the typification of the wise and modest scientist. As science is an ever-evolving discipline, it is necessary for those within the field to adapt their thoughts and beliefs with emerging discoveries. Many are reluctant to concede their errors, as they worry it will threaten their scientific authority, but those who do are frequently lauded for their honesty and bravery in doing so. This phenomenon is generally observed in the context of divisive issues, such as climate change, antibiotic resistance, and carcinogenic chemicals.

Most recently, the use of GMOs has been the hot-button issue, not just within agro-ecology, but science as a whole. A number of researchers and journalists have publically “come out” on one side of the issue or the other.

Thierry Vrain, once a high-profile biotechnologist and genetic engineer, became an anti-GMO spokesperson upon retirement. He now warns of the dangers of genetically modified crops, urging that engineered soy and corn contain toxic and allergenic proteins. Vrain also questions the environmental justification of genetic modification; that these crops have higher yields and require less pesticides is unsubstantiated. Vrain is celebrated as a luminary by the anti-GMO camp, and is frequently quoted by organizations like GMWatch, Food Integrity Now, and Natural Society.

On the other side of the equation, Bill Nye, a previous GMO skeptic, recently came out in support of genetic modification after spending time with Monsanto’s scientists. The Washington Post, Business Insider, EcoWatch, and the Environmental Working Group all praised Nye’s conversion to a pro-GMO stance.

Admitting the error of one’s ways is certainly a courageous and admirable act. However, in situations such as these, perhaps an even bolder act is admitting ignorance. Given the contradictory evidence on the safety and effectiveness of GMOs, one would be remiss to conclusively choose either side.

True, GMOs hold great promise to solve our most pressing health, environmental, and economic concerns. For instance, genetically engineered crops can be manipulated to contain concentrated amounts of certain nutrients of concern in an effort to prevent deficiency-related disease. Golden rice, an engineered variety of rice with high levels of vitamin A, is the most obvious example. Vitamin A deficiency typically afflicts those in developing countries with limited access to food; annually, it causes blindness in as many as 500,000 children, and is responsible for 670,000 infant deaths. By providing necessary vitamin A, golden rice may be a valuable tool to promote ocular health and abate infant mortality.

Similarly, GMOs have significant potential to improve the environmental sustainability of agriculture by decreasing the use of land and chemicals.  Bt-corn is one of such engineered crops that have obviated the need for synthetic pesticides. This corn variety has been modified to express proteins from Bacillus thuringiensis, a bacterium that acts as a biopesticide. As such, Bt-corn is poisonous to pests, who are killed after ingesting the engineered crop. (Bt does not appear to have the same effect on humans, and the EPA says it can be ingested without deleterious consequences.)

Because this variety of corn acts as its own pesticide, the use of additional chemical pesticides is not always necessary. This could decrease exposure to and consumption of potentially toxic chemicals. According to a 2012 study at Washington State University, Bt crops have reduced pesticide use by 123 million pounds since 1996. It should be noted, however, that overall pesticide use increased by 404 million pounds, largely due to genetically engineered, herbicide resistant crops.

There are a number of other salient arguments in support of GM agriculture.  Certain engineered crops enable farmers to implement no-till methods, ultimately reducing soil erosion and, less directly, water pollution and eutrophication. GM crops may be a more economically reliable option for farmers, as they are less susceptible to the contingencies of weather, weeds, and insects. Furthermore, engineered crop varieties often have greater yield than their non-modified counterparts. The benefit of this is twofold: farmers will be guaranteed a greater payback for the same amount of land, while unsuitable land can be retired without threatening food supply.

Given the aforementioned benefits of genetic modification, it seems that opposing these wonder-crops would be an act of irrational skepticism. But for every argument in support of GMOs, there is an equally compelling argument against. For one, there is the concern of safety. Although GMO proponents maintain that modified crops are safe for human consumption, the research that supports this claim are typically short-term, experimental studies. The long-term effects of consuming genetically modified foods are unknown.

Of primary concern is allergenicity, as introducing allergenic protein sequences into a non-allergenic organism could possibly render the latter allergenic. Whether allergenicity is likely to occur in GM crops is a contested issue; many argue that the probability is no greater than in non-modified foods. Regardless, the causes of food allergies are still largely misunderstood, and the research on the safety of genetically engineered crops is relatively nascent, making it difficult to accurately assess the possibility of allergenicity.

Even if allergenicity is not a problem, there are other health risks associated with genetic modification.  As previously mentioned, herbicide-resistant GM crops have resulted in greater overall application of weed killers in the United States. Glyphosate (popularly known as Roundup), the most popular herbicide in the United States is, was recently identified by the World Health Organization as a likely carcinogen. Because a large portion of our food supply is treated with glyphosate, it is reasonable to ask about the ramifications of ingesting trace amounts on a daily basis.  In large quantities, it can be fatal.

The toxicity of herbicides is hazardous not just to humans, but to livestock and wildlife as well. Liberal herbicide application can affect all flora and fauna within an ecosystem, poisoning pollinators, and hindering the growth of plants that rely on them. In turn, the animals that use those plants as sustenance or habitat may also be threatened, causing a chain reaction that can shatter an entire ecosystem.

The possibility of pesticide resistance is of additional concern. As we introduce more Bt crops, the number of resistant species increases. There are now five pest species that exhibit resistance, and that number is expected to grow. The issue of herbicide resistance is even more prevalent; there are at least 30 weed species worldwide that exhibit glyphosate resistance. Pesticide and herbicide resistance is not a matter of inconvenience. As weeds and insects become resistant to chemicals, they evolve into “superweeds” and “superbugs,” extremely resilient species that, in large enough populations, will threaten our food supply.

The intent of presenting these arguments is not to sway you towards or away from GMOs; indeed, it is just the opposite. Genetic modification is an extraordinarily nuanced issue, and each application varies significantly in its benefits and its risks. By framing it as a black-and-white matter, one ignores the hundreds of gradations between. It is clear, then, that the question at hand is not “yes or no?” but rather “when?” “how?” and “why?” And in allowing for greater complexity in our discussion of GMOs, we will be more pragmatic in our future development and use of biotechnology.

Hannah Packman is a first year student in the Agriculture, Food and Environment masters program. When she isn’t busy filling her head with food-related facts, she enjoys filling her stomach with food-related objects.

Vitamin K2: What Is It, Where Is It, What Does It Do, and Do I Need It?

by Emily Finnan, RD

10 years ago, vitamin K2 was largely unheard of. Today, it’s a top Google search term, the subject of numerous books, and over 500 supplements are sold on Amazon. In part, due to a growing number of vitamin K2 supporters who champion it as a necessity for bone and heart health. However, 76 years after its discovery, it seems we still have more questions than answers about this important nutrient.

What is it?

Vitamin K2 isn’t a new nutrient; it’s simply a form of vitamin K. Vitamin K is a term for a group of essential

compounds that all contain the chemical structure methyl-1,4-napthoquinone.  This group can be further divided into vitamin K1, K2 and K3. Vitamin K2, or menaquinones, is a term for several compounds named MK-4 through MK-13.

Where is it?

Vitamin K2 is predominantly made by bacteria. It’s found in fermented foods and animal products.

MK-7 and MK-4 are the two most talked about and studied forms of vitamin K2. MK-7 is the form found in Natto, a Japanese fermented soy product. MK-4 is the form found in animal products. Additionally, your body likely makes MK-4 from vitamin K1 eaten. The other “MKs” are made by different strains of bacteria found in fermented foods or in your gastrointestinal tracts. It’s debated, but likely a minimal amount of vitamin K from the gut is actually absorbed and used by your body.

Vitamin K1, or phylloquinone, is made by plants. It’s found in a variety of vegetables, some fruits, and vegetable oils. Leafy greens are an especially good source. 90% of the vitamin K we eat is in this form.

Vitamin K3, or menadione, is a synthetic precursor of vitamin K. It isn’t recommend for humans, but it is used in animal feed.

What about grass-fed?

Blogs that tout the benefits of vitamin K2 likely recommend grass-fed animal products as the premier source. Grass does contain vitamin K1. But a cow’s primary source of vitamin K comes from large colonies of K2-producing bacteria that live in their ruminant stomachs. Conventionally raised livestock are frequently given antibiotics, which can diminish gut bacteria. However, livestock feed is typically fortified with vitamin K3, which the animal directly converts o MK-4.

MK-4 is present in conventionally-raised dairy, beef, poultry, and other animal-based foods. A study conducted in the Netherlands, found no substantial difference in MK-4 content between wild, free-range, and “intensively raised” meat, dairy, and eggs. Currently, there isn’t evidence to support grass-fed animals as a superior source of MK-4.

What does it do?

All forms of vitamin K help carboxylate (add extra acid groups) to certain proteins, which helps the proteins’ function. Un-carboxylated vitamin K-dependent proteins are those that vitamin K has not acted on.

Vitamin K & blood clotting

This is vitamin K’s most studied role. Vitamin K is essential for proper blood clotting. A person with a severe vitamin K deficiency, which is rare, will have clotting problems.

Vitamin K & bone

Vitamin K carboxylates the bone protein, osteocalcin, allowing it to act on bone. This has led to the hypothesis that a high level of un-carboxylated osteocalcin is an indicator of vitamin K insufficiency and poor bone health. Vitamin K2 and K1 have been shown to increase osteocalcin carboxylation. Additionally, researchers have found both inside bone.

Two large Japanese observational studies, totaling almost 3,000 people, found positive associations between dietary MK-7 and increased bone mineral density. However, observational trials can’t determine causation. People who eat more vitamin K, might have a healthier diet and lifestyle; especially because vitamin K is found in typically healthful foods.

Randomized controlled trials (RCT) can help determine causation. 11 RCTs have been conducted with 15 to 45 milligram (or 15,000 to 45,000 micrograms) MK-4 supplements. The majority do report that the MK-4 supplement group had a positive result in at least one marker of bone health.  In Japan, where most of these trials were conducted, MK-4 supplements are routinely used as part of osteoporosis treatment. Of note, these doses of vitamin K are much higher than you can obtain from food. Vitamin K is therefore being used as a medication, not as a dietary factor.

RCTs and observational trials conducted using vitamin K1 are inconclusive.

Vitamin K & vascular calcification

Vitamin K may have a role in preventing vascular calcification, a major risk factor for heart disease. This is through vitamin K’s carboxylation of matrix Gla-protein (MGP). It’s not fully understood, but un-carboxylated MGP may increase vascular calcification.  Vitamin K1 and MK-4 both reduce un-carboxylated MGP.

Only one observational, cohort study has shown a positive association between total dietary vitamin K2 intake and reduced vascular calcification. Observational studies using vitamin K1 intake show no effect.  An RCT, conducted at the Jean Mayer USDA Human Nutrition Research Center on Aging (HNRCA), found that vitamin K1 supplementation did slow progression of calcification in those with pre-existing coronary artery calcification.

Do I need it?

The optimum level of vitamin K in the diet is unclear. The adequate intake (AI) of vitamin K, for men 19 years and older, is 120 micrograms (mcg). This was based simply on the amount of vitamin K healthy people eat. The AI doesn’t specify targets of vitamin K1 versus K2. It’s been suggested that the amount of vitamin K needed to prevent clotting problems is less than 10 mcg per day; but at least 1,000 mcg per is needed for optimum bone density.

Below is a table of vitamin K content in various foods. The Vitamin K1 data is predominately from the USDA Nutrient Database. Vitamin K2 data was obtained from three individual studies: here, here, and here.

vitaminktable

*unknown fat-content

Many books and health blogs (here, here, here, and here) claim that the US population is widely deficient  in vitamin K2, which they report is specifically essential for bone and vascular health. However, there is a lot more we need learn about vitamin K2. Do vitamin K2 and K1 actually have different functions in our body? If we can make vitamin K2 from K1, does it even matter how much K2 we eat? We don’t know what a sufficient level of vitamin K2 is, let alone a deficient level, or even the best biomarker of K2 status. Furthermore, if 1,000 mcg is the true optimum intake then it seems it would be much easier to reach this level by focusing on vitamin K1 sources rather than K2- you’d need to eat 7 pounds of blue cheese or 300 eggs a day to reach 1,000 mcg!

The good news is that a varied diet that includes variety of vegetables, leafy greens, as well as meats and dairy can supply a person with well over the AI of vitamin K. There is also no known harm of taking high-dose vitamin K supplements. My advice: eat a varied diet that includes servings of vitamin K-rich vegetables and fermented foods. These foods are great for other reasons too– high in other important micronutrients and fermented foods contain beneficial probiotics. If you’re thinking about taking a vitamin K2 supplement, talk to your doctor as vitamin K does interact with some medications.

Emily Finnan is a dietitian and finishing her first year in the Biochemical and Molecular Nutrition master’s program.  She’ll be getting acquainted with vitamin K this summer, completing a practicum in the HNRCA’s vitamin K laboratory.

Are Your Diet Choices Based in “Fact” or “Faith?” One Religion Professor Thinks It’s the Latter

by Katherine Pett

Looking for a nutritional antidote to food fears? Take a look at new release The Gluten Lie by Alan Levinovitz, PhD, and stop being scared of your sandwich.

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Despite what the sinister cover of The Gluten Lie by Alan Levinovitz, PhD, suggests, this book is not about gluten… entirely. When I first picked it up, I assumed the author meant to proclaim that gluten sensitivity, the diagnosis du jour, is nonexistent. But the book makes little attempt to determine what is and isn’t healthy. In fact, it’s the exact opposite of a diet book.

A religion professor at James Madison University, Levinovitz remains agnostic about the existence of gluten sensitivity: to him, it may exist or may not. In fact, he takes this neutral tone with every food fad he discusses, from banishing sugar to forbidding fat. There is evidence for and against each recommendation, but not as much as you’d think.

Levinovitz is primarily concerned with the belief systems that cause sweeping dietary crazes. As a professor of religion, no one is more capable of delivering the Good Word: Many of our beliefs about food are more religious than rational in nature. We unconsciously base food choices and food fears on faith, not facts.

The strict-sounding title is based on the book’s thesis: If you tell people something is true when the research is inconclusive, it’s a lie. Unlike religious leaders for whom myths are tools to give hope and guidance to a congregation, people who invoke science—rather than God—to inspire behavior change have an obligation to the truth, the whole truth, and nothing but the truth.

In the book, Levinovitz uncovers which nutrition “facts” are more rooted in legend than reality and reveals the (sometimes sordid) history behind them. For each of these hotly-debated food elements (ex., gluten, fat, salt, and sugar), there are authorities who swear that eliminating it will fix your life.

For example, gluten restriction, especially as a part of the CrossFit/Paleo paradigm, can seem a little, well, cultish. But it’s nothing compared to the originators of sodium-restriction who formed an actual cult. Known as “Ricers,” these people were a group of extremist dieters who followed low-sodium, rice-diet guru Dr. Walter Kemper of Duke University. The Rice Diet was not unlike today’s Paleo or Bulletproof diets in that it attracted a lot of attention and plenty of celebrity adherents, such as Buddy Hacket, Dom DeLuise, and multiple NFL players. It was different, however, in the sense that its founder kept a harem of devoted dieting women in houses he owned, connected their housing via walkways, and was named an heir in their wills.

But why, you might be wondering, would people believe that a no-sodium, all-rice diet will solve your problems? Especially now when people have access to Google, PubMed, and a world of scientific references and textbooks that tell us that balance is key to health? It turns out that it isn’t hard to make a convincing and seemingly science-based argument. All you need to do is pick a few studies, conveniently tweak the details so they match your framework, add a few scary statistics and unproven claims and, boom, you’ve written the next Wheat Belly.

To prove his point, Levinovitz shows how it’s done with a diet of his own invention: The UNpacked DietTM. In the book’s last chapter, Levinovitz creates a mock first chapter of a “science-based” diet book that explains how plastic packaging will make you sick and fat. The diet comes complete with numerous citations, references to seemingly authoritative researchers, and excellent graphics tracking bottled water use and the rise in obesity. Even though I knew the diet was meant to be facetious, I found myself seriously considering some of the arguments. “That sounds reasonable,” I heard my inner-voice saying.

Just after he nearly convinced me that plastic really is the source of all my problems, Levinovitz then repeats the entire chapter, but with cartoon thought bubbles pointing out each flaw in the reasoning. Every single point that seemed so meaningful is actually a careful misrepresentation of evidence that doesn’t prove nearly as much as the “author” would like. The similarities between the writing in The UNpacked DietTM and any other diet book gracing the bestseller list are uncanny. In fact, it made me wonder if Dr. Levinovitz missed an opportunity by deciding to pull back the curtain on the genre, rather than to partake in its riches.

Overall take? If you work in wellness or you’re just an avid follower of nutrition in the news, you need this book. If you have an annoying friend who bugs you about the newest “antinutrient,” you need this book so you can toss it to your annoying friend while you run away. This book is timely, given the wake of The Food Babe, expands understanding of the belief systems that underlie our country’s disordered eating culture, and acts as a reset button for our own food prejudices.

While he may not make the point directly, it is implied throughout the book: You can’t cheat death with “one simple trick” to get rid of belly fat. There is no toxic nutrient that causes all disease. So chill out. Eat your sandwich.

Interested? Check out a recent lecture by Levinovitz, where he explains the concept of his book:

Katherine Pett is a first-year Biochemical and Molecular Nutrition student at The Friedman School.  Follow her on twitter @smarfdoc or contact her at katherine.docimo@tufts.edu.