Kevin Klatt, PhD, RD

berkley.edu With the ever growing emphasis on understanding how human nutrient needs evolved, I think it's pertinent to remember all of the forces of evolution -- I said back when I first started this blog that there's a strong chance that specific human populations likely have nutrition/metabolism variants related to the forces of evolution besides selection in a specific nutritope. Recent evidence suggests that gene flow may have played quite an important role in the evolution of metabolism. This evidence stems from the recent sequencing of a high quality Neanderthal genome by Svaante Paabo's group at the Max Planck Institute for Evolutionary Anthropology, leading evolutionary biologists and anthropologists to suggest that ancestral populations interbred with Neanderthals. Neanderthals and humans likely diverged from their last common ancestor, which has eluded paleoanthropologists (1), about 1 mya; however, molecular clock data suggests a more recent LCA (2). Nea...

Credit: Hindawi.com               When it comes to Omega 3's, form and source are quite important, both from a health and evolutionary perspective. There are three kinds of these fatty acids: alpha linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). ALA is the shorter plant form, and currently the only form considered essential; ALA can be elongated into the longer chain EPA/DHA, found in fish and phytoplankton, via fatty acid desaturases (enzymes your liver produces).               Referring to ALA as the only essential omega 3 fatty acid has been an issue of contention in the field of nutritional sciences. EPA/DHA, at low doses, are thought to be potent anti-inflammatory agents, lower triglycerides , and help maintain cholesterol homeostasis, via decreasing lipogenic gene expression in the liver (2), all having prof...

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...

Alkaline diets have blown up in popularity. The theory is that over a long time, eating more foods that act acidic in the body (not necessarily having to be acidic in its food form outside the body) will lead to a leaching of calcium from the bones to neutralize blood pH. Some foods claimed to acidify the blood are simple starches, sodas (rich in phosphoric acid) and animal products (higher in cysteine/methionine, sulphuric amino acid). The blood sits at a pH of 7.34-7.45 - this is very tightly regulated, because too high or too low a pH can alter the rates of enzymatic reactions, protein structures, etc. You wouldn't make it too long if your pH dropped out of this homeostatic range. This all sounds fine and dandy right? More acid-acting foods, more calcium removed from bone to neutralize this. I've said this before - there isn't always a simplistic logic that allows you to infer anything about health.I've always been very apprehensive to accept this theory, because...

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...

The moderate viewpoint always seems to be most truthful, from my experiences. This is especially true in nutrition. I have read articles by MDs stating that nutrition isn't a big issue and there's no evidence showing that fruits and vegetables lead to long life. I have also read alternative health providers stating that eating a raw vegan diet will stave away every ailment known to man. I find this polarized view to be quite vexing - and part of the reason that I'm interested in the intersection of genetics and nutrition. There is definitely no questioning that people benefit from increasing their consumption of nutrient dense foods - getting back to nature is definitely a good thing in a secure food environment; choosing minimally processed foods increases the amounts of vitamins, mineral, antioxidants and phytonutrients that you'll get. It's not all about genetics; people don't become obese due to some genetic defect alone - there needs to be a calorically r...