Kevin Klatt, PhD, RD

It's really hard to talk nutrition with someone, especially when you stick to the science and they can throw out sentiment after sentiment - sentiment always sounds better than science! Here's a few common sentiments I get all the time that are so far from scientific: 1. "But so and so did it and lost a ton of weight!" - This one's from the people who never took a statistics course. 'Miley Cyrus went gluten-free and look how healthy she is!!' is known as an n=1 situation - one person's experiences don't say much, and nothing controls for confounding factors. If we took every anecdote of healthy people, whether they were olympic athletes or individuals who lost 400lbs, we'd get about 100+ diets out of it (go look at the diet section of your local book store - I'd say about a 100) . What one person did to stay healthy only shows the dietary plasticity of the human body - we can eat a variety of things, or not eat a variety of things, and b...

It seems like everyone has a bit of a cough or sore throat today. That common cold is a bit annoying but luckily, there's a million claims about any number of vitamin/mineral/herb supplements that can help your immune system out!  What holds up to the science? What can you tell your patients/friends/family? Here's a quick breakdown of the evidence for/against the popular ones: 1. Vitamin C - Go into any drug store in the winter and you're bombarded by Emergen- C and Airborne as soon as you enter. Their box covers usually advertise that they've got 1000mg of vitamin C - yay!! right? The clinical trials are actually pretty dim regarding Vitamin C's ability to prevent or treat the common cold . The latest Cochrane review (1) on vitamin C supplementation showed a very small benefit for regular supplementation with Vitamin C (generally over 1g/day), and no effect for therapeutic use (started at beginning of onset). The only individuals that Vitamin C may be beneficial...

If you didn't hear, there was a pretty controversial report in the Annals of Medicine put out claiming that consumers should stop wasting their money on Multivitamins (1). In my opinon, a more appropriate summary is to not expect anything that great from popping your daily. I've got a lot of thoughts on this issue so let's break it down: 1.  May the Odds be Ever in your Favor - tossing a bunch of vitamins and minerals into the intestines at once is a bit like the Hunger Games- you've got a bunch of competitors, some will beat out others (for absorption) and maybe one will win out (be highly bioavailable) at the end. if you've ever taken a course on micronutrient metabolism, you'll probably hear this report and think ..'duh?' Mineral bioavailability is dependent upon a number of factors, and is largely inhibited by the presence of other minerals. Think back to your high school chemistry days - what happens when you put a bunch of positive charged min...

I just got back from the American Society for Nutrition's Advances and Controversies in Clinical Nutrition conference and came back with a lot of ideas for blogging.  I was happy to see a number of things i've blogged about and my thoughts on clinical nutrition were covered at the conference, with similar conclusions - I identify more as a scientist and less as a future clinician so it's good to see i'm not totally off base with reality. One very interesting talk was given by the chair of the Food and Nutrition Board (FNB) of the Institute of Medicine (IoM). Before I go on to discuss some relevant points from her talk, there's a few definition you'll need to be sure of (1): Dietary Reference Intake (DRI's ): reference values that are quantitative estimates of nutrient intakes to be used for planning and assessing diets for healthy people (Recommended intakes and Upper Limits) Recommended Dietary Allowance (RDA) (newly called AMDR): the average daily ...

Pigmentation is a great model for teaching evolution and demonstrating the concept of a polygenic trait - there are a number of alleles at different loci at variable frequencies throughout the population.  This variability has been disproportionately seen across a latitudinal cline, with darker skin tones being present around equatorial regions, and a lightening seen as latitude increases. An estimated 88% of total pigmentation variation in humans can be explained by geographic differences; for reference, geography can only explain 13% of craniometric variation, another highly quantitative trait. Considering the recent evolution of modern humans, this drastic geographic distribution in pigmentation has been thought to be the result of strong selective pressures. The major differences in pigmentation are due to the amount and type of melanin synthesized in the melanocytes, and the shape and distribution of the melanosomes, organelles that transport and store melanin . Melanins are...

I really applaud anyone who is trying to make positive changes to their lifestyle, especially by improving their nutrition but, few things annoy me more than massively disseminated misinformation. The most virulent case of this is linoleic acid, an omega 6 (n-6) fatty acid. Do one google search of "Omega 6's and Inflammation" and you'll find articles on every internet health site, written by MDs/RDs/etc etc, telling you that Omega 6's, like those found in vegetable oils, are virtually the cause of every modern day ailment, from heart disease, to acne and arthritis. They'll cite you information stating that the n-6:n-3 fatty acid ratio is all out of whack. There seem to be 2 reasons that people claim linoleic acid is pro-inflammatory. 1, because it is a precursor to inflammatory molecules in the body. 2, because it is subject to oxidation, and these oxidative endproducts (reactive carbonyl compounds, ketones, aldehydes) incite an immune response . 1. Lino...

One of the most common 'anti-nutrients'/organic compounds that alternative health/ancestral diet followers seem to talk about is phytic acid. The structure of phytic acid contains an inositol group (similar to B-vitamin structures) and 6 phosphate groups. Phytic acid exists in plant foods, particularly high in nuts, seeds, whole grains and legumes. Phytic acid is a particularly important reservoir of phosphorous and other mineral cations for a plant - plants contain the enzyme phytase, which can hydrolyze the bonds between phytic acid and its bound minerals (phytic acid:mineral complexes are known as phytates). Humans do not produce phytase, though some bacteria in the human small intestine may have phytase activity, allowing for the release of a small fraction of the bound mineral. The human GI tract's pH, also, does not facilitate the liberation of minerals from their phytate complexes. Phytic acid most commonly binds to non-heme iron, zinc, and calcium (1). From an evo...

A study came out in Gastroenterology (1), that I find to be nicely timed with my most recent post on the need for controlled studies surrounding issues like gluten. I am in no way saying this is the be all end all for the gluten-free fad, but this is a scientific step in the right direction for understanding the role of gluten, if any, in medical conditions. A lot of people are avoiding gluten for a number of reasons - they think it causes weight gain, it's 'toxic', causes GI discomfort, skin problems, etc etc. Much of the information that pushes gluten-free diets is anecdotal, and doesn't control for confounding factors - when it comes to food, there are hundreds of food components/chemicals to consider, at both the macro and micronutrient levels, as well as the many interactions between said components. I must admit a pretty non-scientific sentiment- I've always been a bit skeptical of the scientific community's acceptance of gluten sensitivity. Not that ...

If you're reading this expecting me to either endorse or stand in opposition to high-protein diets, turn back now. In nutrition, it's difficult to make a simplistic recommendation out of the mounds of scientific literature that exists on a topic - I can't imagine the stress that the Food and Nutrition Board of the Institute of Medicine (IOM) is under while making population-level recommendations. Protein is probably the most well studied of the macronutrients, from a physiological and biochemical perspective - the worldwide obsession with ensuring adequate 'complete' protein intake enveloped a lot nutritional sciences research in the 1900's. From this research, we learned a lot about amino acid metabolism/catabolism and understand the basic needs of most humans. It's known now that it's not necessary to only eat complete proteins, and that eating a combination of plant foods can provide all of the amino acids - hence, vegetarians not completely wasting...

That title is half a fiber joke and half pointing to the need for a Nutrition Fact Check website (similar to the politics version ). Fiber also happens to be a great way to slow down digestion, to reduce the surge of blood sugar following a higher carbohydrate meal and maintain satiety for longer (1). I see/hear a lot of things about Glycemic Index and many of them are not factual, misguided or simply untrue. The most common myth I've heard lately is that all whole grains have the same Glycemic Index value as processed grains (it varies a lot, some do , some don't - see below). Besides the fact that one should be using the Glycemic Load and ditching the Glycemic Index, it's hard to substantiate those rumors - I don't like to call out web sites, simply type into google "whole wheat same GI as white wheat" if you want to see the numerous websites passing around this myth. If you would like a reliable source regarding general Glycemic Indices, try this Ha...

Here's the best recipe for an awesome nutrition article: 1. Ignore Health - Health Sshmealth. It's all about body image. If you're writing an article about nutrition, make sure to convince the reader that their primary goal is weight loss and/or achieving physical perfection. Longevity is so lame; who wants to live until 85 if you don't look sexy doing it?? If they haven't been convinced by every TV commercial and diet out that they should be unhappy with their bodies, you may want to tie up those loose ends and seal the deal - a high self esteem adds like 10 lbs, i've heard. If they don't already believe that weight loss is super difficult, you may want to also cement that concept into their minds - i mean, weight loss is super hard, but luckily, they've found your program. You may consider giving yourself the title of 'the Christ' at this point, but humility promotes fatty acid oxidation. 2. Trash the Current Recommendations - obviously, th...