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.

Not Another Soylent Article?! Get the Real Scoop on This Cheap Powder

by Michelle Pearson

Soylent is nothing new, and this is not the first article, but it may be the first to take a practical look beyond the gimmick. Soylent is for people!

Lovingly named after the movie Soylent Green about a post-apocalyptic world without food. Yes, Soylent could help you survive an apocalypse, so you can avoid eating people. Ironic, huh? It’s not a silver bullet for recovering food addicts or those looking to ditch eating altogether. Yes, you can live on Soylent, but should you? There’s no research on Soylent, so the jury is still out. The opinion of Soylent does not have to be as cut and dried as its form. There are plenty of uses for it! Let’s explore them together.

Soylent is not alone, but at $1.54 a meal, it might be the cheapest. The World Health Organization has been developing similar items for years for nutrition assistance. Hospitals routinely use liquid nutrition products for patients unable to eat. The marketplace is saturated with brands like Raw Meal, Boost, Ensure, and Slimfast. Soylent is just the newest edition and fashionably late.

First be warned! Soylent is not your sugar-sweetened pudding-flavored soylent.pngpredecessors. It tastes like, well, nothing. Not the same as the sought after Soylent cookie in the movie. The second formulation does have improved taste and texture. The website even has smoothie suggestions (shown right). Think of it as a blank slate to create whatever flavors you want. Then just scoop and add water. If nutrition is what you seek, the first formulation focuses more on health than on palatability. It might be worth taking a look, but be careful. Some consumers reported side effects….

Average Joe said it best in his comment titled “Is she the one?” on Amazon reviews: “Soylent gives you the kind of gas that is absolutely perfect for stress-testing your marriage. If you aren’t sure about whether your wife truly loves you or not, Soylent WILL give you an answer”.

We have established that Soylent is not people. Do you know what else Soylent is not? It’s not jam-packed with fruits and vegetables either. Gasp! Then what is it? The powder is a compilation of 40% fat, 45% carbohydrates, and 15% protein. Personally, I wish it were higher in protein and lower in fat. One great thing about Soylent is that it is open sourced, which means you can create and customize your own version! Then again, if you have no time to cook, are you really going to DIY a supplement? Besides time, Soylent saves money, reduces food waste, is lightweight, and has a long shelf life. I have also read it makes a decent stain remover.

Soylent1The fats in Soylent are canola and sunflower oil. The carbohydrates are oats and isomaltulose, a slower absorbing sugar substitute. The proteins come from rice flour and the whole thing is fortified with vitamins and minerals to meet the RDAs. Can a person live on canola, sunflower, oats, sugar, and rice? The creator Rob Rhinehart says he has been doing it for years! I have found Soylent useful this semester, but I only add a scoop to “flesh” out my smoothies. I find Soylent very filling. It’s an easy way to stay satiated at school without having to prepare and pack much food. Still, are the ingredients healthy?

The beta glucans in oats lower cholesterol levels and isomaltulose does not cause cavities. Brown rice flour is a complete source of protein, containing all nine essential amino acids. The overall protein content is comparable to soy and whey. A friend of mine adds whey protein to his Soylent for strength training. He is in his cut phase, supplementing two meals a day with Soylent to track calories with great success. He finds his version of Soylent to be a nice post exercise meal for quick nutrition within the hour window of replenishing glycogen. Could Soylent be the new chocolate milk?

The first two ingredients in Soylent are canola and sunflower oil. The good news is these fats are high in omega-3 fats that reduce the risk of cardiovascular disease. The downside is that such a large amount of fat could cause digestive problems. Probably why they ditched the flaxseed oil in the first version, or why Average Joe had so much gas. “Fat content is most often the culprit of digestive issues,” says Dr. Kathrina Prelack, Director of Clinical Nutrition at Shriners Hospital. She explains that liquid nutrition used in the hospital has high medium chain fatty acids to prevent distress. These fats are absorbed more easily than long chains. Soylent lacks these and may cause discomfort.

Another problem is lack of fiber. Women should get 25 g, and men should have a whopping 38 g every day. Soylent has a measly 3 g of fiber per serving, not even adding up to half of what a person needs in a day. Still, this may be a lot more fiber than some people get. In 2010, over 90% of Americans were not getting enough. Maybe this is why our friend Average Joe was having issues…This writer has had no issues and neither has my friend.

Soylent also lacks phytonutrients. These are protective chemicals in plants shown to have health benefits. There are many known phytonutrients, such as flavanols in chocolate and lycopene in tomatoes, with more to be discovered, but supplementing them may not be the answer. Eating foods in their entirety has shown to have better health benefits than consuming the same processed versions. The ingredients in Soylent do have health benefits, but they are incomplete. The real issue here is variety. Soylent limits the diet to just a few foods, and it may be missing other things the body needs from whole foods.

Nutrition aside, eating also involves time, cost, planning, and preparation. Why else would Soylent become so popular? Last year, Soylent made $10 million in profits. Soylent may not be the nutritional quick fix, or the end of food, but it can help. You may not want to stop eating, but why not take advantage of this new product? It’s working for Rob Rhinehart, for busy moms, and the Silicon Valley industry. It’s working for my friend and me.

Soylent has a lot of potential. For instance, this lightweight, calorically dense powder is a hiker’s dream! It might also displace the canned goods you have stored in your bunker. The frequent traveler might want to toss a bag of Soylent in their suitcase as a backup. Truck drivers could do wonders for their heath switching to Soylent if they currently survive on diner food. Plenty of people are scarfing down pizza, burgers, subs, and fries right now. Surely, Soylent is a better choice.

Benefits Drawbacks
Reduces food waste Not Organic
Vegan Has GMO’s
Nut Free Has Gluten
Lactose Free Has Soy
Quick & Easy Tasteless
Low cost ($1.54 a meal) Not Kosher
Control calories Low protein for building muscle
Light weight No phytonutrients
Long shelf life Lacks variety
Healthy fats High in fat
Higher fiber than most processed foods Low fiber compared to healthy foods
Better alternative to unhealthy foods Not as healthy as a balanced, varied diet

 Michelle Pearson is a second-year Master’s student studying Biochemical and Molecular Nutrition.

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.


*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.

Fenugreek Speaks!

by Nusheen Orandi

You may think you’ve never heard of this legume, especially since it sounds like an ancient language or something. But its supplement form hit health food stores and is becoming an area of interest in nutrition research. You might even see it in grocery stores “superfood” exclamations soon. What makes people with diabetes or high cholesterol look to fenugreek for help?

What Is Fenugreek?

Common in the diet of Iran, Egypt, and Nepal, people use both the leaves and seeds of fenugreek in cooking, making it a unique and sustainable item. Fenugreek has a variety of uses, including:

  • Integration into spices: many contain fenugreek in its powdered form to add flavor to stews, sauces, and curries.
  • Seeds are eaten whole or added to many dishes as a legume.
  • Integral part of pita bread: Egyptian cuisine mixes the seeds with maize to make the bread.
  • As a  mircrogreen or herb: they add flavor to Persian stews and Indian curries.

Nutritionally, fenugreek  is a rich source of protein (23-26%), carbohydrates (58%), fiber, calcium, iron, beta-carotene, and other healthful phytochemicals that make it a valuable component to these diets. In fact phytochemicals, natural chemical compounds in plants, found in fenugreek captured the attention of nutrition science research.

Fenugreek for Diabetes

Apparently fenugreek adds healthful advantages to many diets, but why would people with diabetes try eating more of it? Research shows that eating fenugreek might lower blood sugar. Because the seeds contain mucilaginous fiber (a type of soluble fiber) and steroidal sapogenin (steroid compounds in plants), fenugreek might benefit people with diabetes to control their blood sugar. Ancient Chinese and Indian cultures used fenugreek medicinally as an anti-diabetic therapeutic treatment, just by soaking it in hot water and eating it.

Helping High Cholesterol

For the same reasons that suggest lowering blood sugar, fenugreek might also lower blood cholesterol. Although scientific evidence conflicts, a particular study demonstrated how fenugreek could lower LDL (“bad cholesterol”), as seen in many rat studies. However, limited human studies support this finding. Other studies attribute this cholesterol-lowering effect to flavenoids (a type of phytochemical) abundant in fenugreek seeds, specifically naringenin. One study found that fenugreek decreased triglycerides and cholesterol in patients with coronary artery disease

Another Antioxidant

Studies on fenugreek extracts demonstrated that the phenolic compounds in fenugreek, especially the seeds, give it potential as a good antioxidant source. This could explain why fenugreek neighbors other herbal supplements in health food stores.

Future Research

Fenugreek research also surrounds topics like breast milk production, gastrointestinal therapeutic treatments, weight loss, and atherosclerosis prevention, however significant results remain to be seen.

So give fenugreek a go, by adding flavor to this simple red lentil soup.

Nusheen Orandi is a first-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, tensely watching the Tottenham Hotspurs, and cooking and eating with friends and family.

Probiotics: What Do These Bacteria Do?

by Nusheen Orandi

When I’m shopping in the dairy aisle of the grocery store, I stand in front of the yogurt section for a while. When did it get so huge? Greek, Icelandic, Kefir, whole milk, low-fat, non-fat, goat’s milk, and coconut milk are all options. What’s making yogurt so popular? Well, its probiotic nature is one of its claims to fame.

What does probiotic mean?

“Probiotic” describes anything that stimulates the growth of microorganisms in large enough numbers to enhance health. With food, this involves bacteria and yeast that ferment products we love, like beer, yogurt, and cheese. With health, the primary interest lies with gut microflora. Gut microflora affects health and digestion in a number of ways including food intolerances, food allergies, and other forms of gastrointestinal discomfort. This not only sparks nutrition research interests but food industry interests as well, who try to market the “functional foods” that could enhance health.

What makes yogurt so special?

The making of yogurt involves probiotic bacteria. Starter cultures begin the process of fermenting hot pasteurized milk to make yogurt. These starter cultures are bacteria not found in the intestinal tract that include Streptococcus thermophilus and L. delbrueckii ssp. Bulgaricus. However, other bacteria used in yogurt-making are found in the intestinal tract, such as members of the Lactobacillus and Bifidobacterium species. Because these bacteria are also found in the intestinal tract, they are known as “dietary adjuncts.” The bacteria in yogurt produce lactic acid, which reacts with milk protein to give it the creamy texture and tart taste. These bacteria’s ability to be produced in high amounts, withstand long shelf life, and benefit human health give yogurt’s its probiotic reputation.

What are the health benefits of probiotics?

Should we eat another bowl of yogurt or a second pint of Guinness? Microbiology experts think so. Scientific evidence points to many health benefits including anti-microbial activity, anti-diarrheal function, enhanced immune function, and improved lactose intolerance and gastrointestinal function.

Anti-microbial activity

Probiotic bacteria produce organic acids that suppress the multiplication of pathogenic bacteria like E.coli and salmonella, which can make us sick. The increased acidity of the intestinal tract enables this function.

Lactose Intolerance

People who experience discomfort from dairy products due to lactose intolerance can sometimes tolerate yogurt due to the probiotic bacteria. People with lactose intolerance lack sufficient amounts of the enzyme lactase in their intestine. Without enough lactase, people inadequately digest the milk sugar. The probiotic bacteria in yogurt contain an enzyme called b-D-galactosidase that partially digests the lactose in yogurt, making it easier for lactose intolerant people to eat yogurt comfortably.  Research also suggests that probiotic bacteria can enhance lactase activity.

Anti-diarrheal Function

Pathogenic bacteria and antibiotic use can cause diarrhea. Probiotic bacteria compete with diarrhea- causing pathogenic bacteria on epithelial cells in your intestine, which reduces the likelihood of diarrhea. Probiotic bacteria especially help people required to take a lot of antibiotics. The antibiotics reduce the amount of “good” microorganisms in your intestine, which can causes diarrhea symptoms. Probiotics help re-colonize the intestine with these “good” bacteria to improve intestinal movement. Hospitalized people who take a variety of medications may benefit from certain probiotic bacteria.

If probiotic bacteria are so good, should we add more to foods?

Because of the noted benefits of probiotic bacteria, debate surrounds the idea of adding more probiotic bacteria in addition to the ones found in traditionally made yogurt and other fermented products. One example is Activia brand yogurt. Probiotic bacteria are available in powders, capsules, and tablets. However the type, amount, and ratio of added probiotic bacteria remain unclear. Clinical trials raised discussion about whether probiotic bacteria given to infants could decrease food allergies later in life. However, further studies provided inconclusive evidence.

Probiotic bacteria not only help make the food we love, but help our bodies know what to do with it! Although those with dietary restrictions or illness may benefit from added probiotic bacteria, the probiotic bacteria found in our foods may be enough to give the rest of us the potential benefits. It just gives us another reason to maintain a well-balanced diet.

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

How Does a Ketogenic Diet Affect YOU? Part 3: C-Reactive Protein: A Marker of Inflammation

by Katie Mark

The latest craze surrounding the ketogenic diet has us further investigating whether or not a high-fat/low-carbohydrate lifestyle might be an appropriate dietary approach for some people. In this 3-part series (click here for part 1 and part 2), we’re evaluating how the ketogenic diet affects biomarkers.

The ketogenic diet is a very low-carbohydrate (<10% of total calories), moderate protein and high-fat (>70% of total calories) diet. After at least two weeks of keto-adaptation, the body’s energy source switches from glucose to fat.

In part one of “How Does a Ketogenic Diet Affect YOU?” we found studies suggesting that nutritional ketosis lowers fasting glucose and insulin levels and possibly increases insulin sensitivity. In part two, we investigated the impact of ketosis on cortisol. We found that a high-fat, carbohydrate-restricted diet may increase certain forms of cortisol, but blood cortisol levels are only half the story. Further research is needed to clarify the relationship between ketosis and an increase in certain forms of cortisol: the active form (cortisol), the inactive form (cortisone) and metabolites of cortisol from enzymatic breakdown.

Now let’s evaluate how the ketogenic diet affects C-reactive protein (CRP).

Increased CRP: Is there a need to worry?

C-Reactive Protein

C-Reactive Protein Model

CRP is considered a marker of inflammation. The liver makes CRP when inflammation in the body is present. High levels of CRP are influenced by genetics, high stress, exposure to environmental toxins and a sedentary lifestyle. Diet can also impact CRP levels, especially diets high in refined and processed foods.

There are two blood tests to measure CRP. The non-specific test indicates acute CRP levels that result from general inflammation in the body. The more sensitive measure is the highly sensitive CRP (hs-CRP) test, which accurately measures basal levels of CRP by measuring inflammation in blood vessels. The hs-CRP test is the accepted measure to determine the risk for cardiovascular disease (CVD).

Higher CRP levels signify a higher risk for developing CVD and abdominal obesity. Weight loss is known to decrease markers of inflammation such as CRP.

It is believed that a high saturated fat and very low carbohydrate diet (VLCARB) increases the risk for CVD. A study published in Nutrition Metabolism (London) compared a VLCARB diet to two low saturated fat, high carbohydrate diets to determine their effect on body composition and CVD risk. The isocaloric (similar calorie composition) diets were: very low fat (CHO:fat:protein; %SF 70:10:20), high unsaturated fat (50:30:20; 6%) and VLCARB (4:61:35, 20%). The study concluded that weight loss resulted in a reduction of CRP regardless of the dietary macronutrient composition. Yet, it is uncertain whether or not the macronutrient composition of a diet influences inflammation.

A study published in The Journal of American College of Nutrition found an increase in CRP in overweight women who followed a short-term low carbohydrate, high-fat weight loss diet. The study reported that an increase in CRP might have resulted from the oxidative stress caused by this type of diet.

Another study published in Obesity (Silver Spring) looked into the inflammatory response caused by a high-fat, low-carbohydrate weight loss diet (HF) by randomly assigning 19 overweight men and women to either an antioxidant (AS) or placebo (P) supplement. The objective was to see if the antioxidants vitamins C and E could decrease the inflammation reported in a HF diet.

CRP decreased 32% in the AS group and increased 50% for the P group; however, this was statistically insignificant. The HF diet did not decrease CRP within the short-term 7-day study even though other markers of inflammation decreased.

The study could not confirm if oxidative stress was causing the inflammation. It was concluded that further research is needed to determine the different CRP responses over the long term, especially while using antioxidant supplements. This is important considering most fruits and vegetables, which are low in fat, contain antioxidants.

The Verdict

A ketogenic diet may increase CRP levels, but weight loss reduces CRP levels. The reason for the increase in CRP is unclear. One plausible explanation is that low intakes of magnesium, vitamin C and other nutrients while on a ketogenic diet may lead to this effect. When magnesium is low, CRP increases. It has been reported that increased vitamin C intake may reduce high CRP levels.

An imbalance between anti-inflammatory fats (omega-3 fatty acids) and pro-inflammatory fats (omega-6 fatty acids) is another possible explanation. Polyunsaturated vegetable oils primarily contain the pro-inflammatory omega-6 fatty acids. Eating less grain-fed meats and chicken and more grass-fed meats and free-range chicken is also important to consider. Grain-fed animals have higher omega-6s whereas grass-fed animals have higher omega-3s. Omega-3s are anti-inflammatory and important for normal body functions, including regulating blood clotting and building cell membranes in the brain. Omega-3s are also suggested to protect against heart disease.

An elevated CRP level is never a good thing. If you are opting for a ketogenic diet, increasing magnesium and vitamin C intake as well as choosing grass-fed products may reduce CRP levels.

Katie Mark is a first year Nutrition Communication/Master of Public Health student who enjoys road cycling and traveling.

How Does a Ketogenic Diet Affect YOU? Part 2: A Deep Look Into Cortisol

by Katie Mark

Recent high hopes for high-fat diets have us further evaluating the ketogenic diet for a wider population. In this three-part series, we’re examining how the ketogenic diet affects biomarkers. Part 1 of this series investigated what ketosis does for fasting glucose and insulin. In Part 2, we look at how a ketogenic diet may affect cortisol levels.

High-fat…high cortisol…high stress?

Cortisol is considered the “stress hormone,” and it influences blood sugar levels, blood pressure, immune response, and stress response. Chronically elevated levels of circulating cortisol can hinder cognitive performance, disrupt sleep, impede immune function, increase abdominal fat, and cause blood sugar imbalances.

Studies have found that cortisol levels increase on a ketogenic diet, but some say the relationship between ketosis and high cortisol needs to be made clearer. First, chronically elevated cortisol correlates with metabolic syndrome, a group of symptoms such as high blood sugar, excess abdominal fat, and abnormal cholesterol levels that increase the risk for diabetes, heart disease, and cancer.

It seems possible that ketogenic diets may cause metabolic syndrome because higher cortisol levels suggest the onset of metabolic syndrome. However, this isn’t the whole picture: It’s also possible that there are multiple forms of cortisol, and their measurements mean different things.

Cortisol is measured in bodily fluids, including urine, saliva, and blood. Multiple forms of cortisol are measured from these samples: cortisone (the inactive form), free cortisol (the active form), and metabolites of cortisone and cortisol resulting from enzyme activity. Equally important, these levels of cortisol biomarkers can vary depending on the time of day.

A holistic understanding of cortisol metabolism relies on looking at the enzymes 11β-hydroxysteroid dehydrogenase (11β-HSD) and 11β-HSD1 (a subtype of 11β-HSD). 11β-HSD1 is found in every cell, but the highest amounts are found deep within fat cells. In fact, it does not matter if a person’s blood cortisol level is low, medium, or high because a highly active 11β-HSD1 will generate a high amount of cortisol inside cells.

Here is a breakdown of cortisol metabolism:

  • Production: 11β-HSD converts cortisol (active) to cortisone (inactive)
  • Regeneration: 11β-HSD1 converts cortisone to cortisol
  • Clearance: Other enzymes help metabolize cortisone and cortisol into metabolites

The cortisol profile of metabolic syndrome, which the ketogenic diet reverses, consists of:

  • High cortisol production
  • High cortisol clearance rates
  • High 11β-HSD1 expression in adipocytes and low 11β-HSD1 expression in the liver (the location that determines where and when cortisol is regenerated)

Now, let’s see how a 24-hour urine proxy is used for detecting cortisol. This proxy results in a less-than-clear picture because cortisol levels are affected by production, regeneration, and clearance. For instance, if clearance decreased or if regeneration increased, cortisol levels could go up if production stayed the same or lowered. This is analogous to simply measuring someone’s total cholesterol without observing LDL and HDL.

Take home message: levels may appear similar when there is a big difference in cortisol metabolism.

One study, published in The Journal of Clinical Endocrinology and Metabolism, used 17 obese men and randomly assigned them to an ad libitum (eat as much as you want) high fat-low carbohydrate (HF-LC) diet (66% fat, 4% carbohydrate) or moderate fat-moderate carbohydrate (MF-MC) diet (35% fat, 35% carbohydrate) for four weeks.

The study found a reversal of the previously described metabolic syndrome cortisol profile for only the HF-LC group: blood cortisol increased, clearance decreased and regeneration increased (due to an increase in 11β-HSD1 activity in the liver). According to the researchers, the ketogenic diet improved the cortisol profile because it was different from the cortisol profile seen in metabolic syndrome.

Furthermore, even though the MF-MC group lost a similar amount of weight, there was no change in 11β-HSD1 activity. This increase in 11β-HSD1 activity in the HF-LC group was independent of the differences in energy intake and weight loss because the same effect was seen in the controls.

A final component to note is that obesity is associated with high cortisol. However, the connection between obesity and elevated serum levels of cortisol has not always been a consistent connection.

Some people with high stress and lots of abdominal fat had normal or low levels of cortisol in their blood. Usually, chronically elevated levels of cortisol leads to increased adiposity; yet, there have been cases of people with high stress and high cortisol, but no obesity. And as we saw in “The Basics of the Ketogenic Diet,” the ketogenic diet has demonstrated effectiveness as a weight loss tool.

What’s the verdict?

We see that diet, especially a carbohydrate-restricted one such as the ketogenic diet, may increase certain forms of cortisol. But blood cortisol levels are only half the story—cortisol levels inside cells illustrate the other half. Also, cortisol will vary depending on the time of day, with levels highest in the morning. Caffeine, stress, and exercise can also increase cortisol levels.

Ultimately, further research is needed to better understand the connections as to why cortisol increases on a ketogenic diet and if cortisol levels are more affected by other variables, such as the activity of the 11β-HSD1 enzyme.

Katie Mark is a first year Nutrition Communication student from Miami, Florida. Due to Boston’s Snowpocalypse, she does not foresee herself living in Boston in the future, so she will return to South Beach following graduation.


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