High potassium foods have benefits beyond those provided just by potassium. The metabolic pathways that potassium uses to reduce hypertension and osteoporosis are well established. However the other benefits are not as well understood. Nutrigenomics may help explain many of those benefits.
Last week we discussed that nutrigenomics is not yet ready for prime time, though. But large numbers of studies are being done to correlate diet and genetics, and will eventually lead to understanding. One of the areas being most explored is the cardiovascular area.
Last week we discussed a large study of the effect of the gene APOE on cardiovascular disease showing a wide variation in the effect of one form of the gene on cardiovascular disease. One variant (E2/E2) is present in 95% of people who develop familial hyperlipidemia type III, but only 2% of people with E2/E2 develop the disease. Diet may account for the variation in those with the same gene variant.
To help sort out how diet can interact with the APOE gene, a recent Spanish study (1) with 41,000 participants looked at over 500 CHD patients and studied their diet, LDL levels, and APOE genotype. The 3 main variations in the gene are E2, E3, and E4. Since we have 2 copies of our genes, some people are E2/E2, some E2/E3, some E3/E4, etc.
The specific aspect of diet the study looked at was saturated fat intake and how it affected LDL in different genotypes. It also looked at whether alcohol consumption affected how fat intake changed LDL in the different genotypes. Epidemiological studies had shown that in general a small amount of alcohol (especially red wine) lowered LDL and the chances of heart disease.
This study showed that the lowering of LDL by alcohol depended on which variation of APOE you had and how much saturated fat you ate. If your saturated fat intake was less than 10%, alcohol intake had no effect on your LDL, no matter if you were E2 or E4. But if your saturated fat intake was greater than 10% of total calories, alcohol kept the LDL level low if you were E2, but did not keep it low if you were E4.
Before you run out and get a genetic test for your APOE variation so you can figure out if you should have a glass of wine at night to protect against the hamburger you ate, realize this is just one of many studies looking at just one of many possible interactions of the APOE gene with diet.
Each of us has hundreds of similar at-risk gene variants. Each of us eats a different diet. Other tools, mathematical and bioinformatic, will use the nutrigenomic information to help develop which diets are best for which gene combinations.
Eventually all the major interactions will be known, or at least enough that recommendations about diet for those with specific genotypes can be made. Until then the best course is to use some of the known types of diets that have been studied. They work for the people with the most common genotypes for the problem they address, such as the glycemic diet for diabetics or the high potassium diet for hypertension and osteoporosis. These diets help to improve those conditions and may help to prevent them in the first place.
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1. Saturated fat intake and alcohol consumption modulate the association between the APOE polymorphism and risk of future coronary heart disease: a nested case-control study in the Spanish EPIC cohort. Corella D, Portolés O, Arriola L, et al. J Nutr Biochem. 2011 May;22(5):487-94. Epub 2010 Aug 5. PMID: 20688498