Kevin Klatt, PhD, RD

If you haven't heard the comments made by David Attenborough regarding humans having stopped evolving, see this ( http://tinyurl.com/khdapmd ). This post only seeks to further support comments made by prominent evolutionary biologists and anthropologists who have already pointed out the flaws in Attenborough's thinking ( http://tinyurl.com/msy24eh ).  As I've pointed out on this blog before, there's a gap in the understanding of human evolution - a lot of people think that only selection is acting as a force of evolution. Attenborough's comments state that humans have stopped selective forces, with the advent of medicine and birth control, etc etc. This is why I wrote the second blog topic on understanding evolutionary and what we can infer about health - there are more forces of evolution than just selection. Evolution is, simply, the change in allele frequencies over time. Alleles are constantly under the effects of genetic drift, with an allele having the p...

I also write for a dietitian's blog in NYC - if you're interested, check out my post questioning the mantra of moderation over at : http://the-sage.org/post/60752812562/moderation-is-key Everything in Moderation? This is the mantra of the field of nutrition. It states that no one food is bad for you if you consume it in moderation . “Everything in moderation” is a bit confusing - and I imagine to the average person. Should you consume everything in the same moderation? I hope not - how moderately you consume vegetables and how moderately you consume Crisco should hopefully be extremely different levels of moderation. Added sugars are fine to consume in moderation - does that mean you drink a Coca-Cola once a week? Once a month? 4 times a year? What is moderate? Moderate consumption and your ability to thrive on moderate consumption of soda are going to be different depending on your daily schedule, level of activity and even your genes. The biggest issue with ...

If you don't already follow Marion Nestle's blog @ foodpolitics.com, I'd highly recommend checking it more frequently. Her perspective on socio-political issues is a nice counter-point sometimes. In perusing her blog, I came across an action notice by the FDA. The FDA will be studying the effects that nutrient claims have on consumer attitudes and responses. I find that this goes quite nicely with my most recent post on Isolated Nutrients and how the food industry likes to manipulate nutrient content to glorify the healthful components of their products. The FDA notes that it's stance "...  does not encourage the addition of nutrients to certain food products (including sugars or snack foods such as [cookies] candies, and carbonated beverages).  "  The FDA will be giving 15 minutes web-based interviews to 7500 individuals that reflect the U.S. Census data regarding gender, SES, age, education, ethnicity, etc. They will be using mock snacks, candy and carbo...

Besides Nutrition is Toxicology (dosage/concentration), my other mantra is becoming "No Nutrient Works in Isolation". Metabolism is an amazingly interactive system - one dietary change isn't going to have one effect. Anytime anyone says one aspect of nutrition is bad for you, you must think "in what context?" This is similar to thinking about evolution and natural selection - saying one variant is bad for you is misleading - in what environment does that gene have a detrimental outcome? Obviously, there are genetic defects that are not viable - but for gene variants that we associate with long-term health, good/bad are based on context. As I mentioned before in the folic acid post, the most widespread TT variant of MTHFR seems to be detrimental for maintaining methylation - but probably only in an environment where folic acid and riboflavin intake is low. A quick google search on Fructose and Health effects will take you to websites explaining tha...

Part 1 focused much more on the types of folate, how they get into cells, and the genetic variants that effect folate-related enzymes and their activity. All fine and dandy background information - Folate's most interesting role, to me, is in its variable effects on genomic methylation aka Epigenetics. Quick background on genomic methylation - different CpG dinucleotides/islands/shores located throughout the genome have the potential to be methylated. This, alongside histone modifications, are responsible for cell type-specific expression patterns, X inactivation in females, silencing of transposable elements and some of the inter-individual variations in expression levels of different proteins that are not explained by coding sequences/other environmental stresses. The thinking is that the methyl groups inhibit transcription factor binding and subsequent expression rates. NOTE: tissues are extremely heterogeneous organs, filled with multiple cell types - methylation levels are e...

A new Nature article came out the other day that addresses a major question in the story of lactase persistence, one of the strongest gene-culture-selection interactions: did hunter-gatherer populations adopt dairy'ing or did dairy'ing cultures migrate and replace these HG populations? I really love this type of research, not only for its profound insight into the past but also the interdisciplinary team that participated in elucidating these facts. I often find myself thinking I need to be a biochemist/molecular biologist/genomicist/bioinformatician to answer all the  questions I have about nutrigenomics - but in this effort alone, there were anthropologists, paleogeneticists, bioarchaeologists, mathematicians, and archaezoologists. To solve the issue of dairying's origins, researchers looked at the bone remains - since calves need to be killed earlier than a cow raised for slaughter, looking at a bone's age can give insight into whether individuals in the time per...