Stephen Barnes, PhD, Department of Pharmacology and Toxicology, and Center for Nutrient-Gene Interaction in CancerPrevention, University of Alabama at Birmingham, and the Purdue University-University of Alabama at Birmingham Botanicals Center for Age-Related Disease, Birmingham, AL 35294

Nutritional genomics offers a way to optimize human health and the quality of life. It is an attractive endeavor, but one with substantial challenges. It encompasses almost all known aspects of science, ranging from the genomes of humans, plants and microorganisms, to the highest levels of food science, analytical science, computing and statistics of large systems, as well as human behavior. The underlying biochemistry that is targeted by the principal issues in nutritional genomics is described and entails genomics, transcriptomics, proteomics and metabolomics. A major feature relevant to nutritional genomics is the single nucleotide polymorphisms in genes that interact with nutrients and other bioactive food components. These genetic changes may lead to alterations in absorption, metabolism and functional responses to bioactive nutritional factors. Bioactive food components may also regulate gene expression at the transcriptome, protein abundance and/or protein turnover levels. Even if all of these variables are known, additional variables to be taken into account include the nutritional variability of the food (unprocessed and processed), the amount that is actually eaten, and the eating-related behaviors of those consuming the food. These challenges are explored within the context of soy intake. Finally, the importance of international co-operation in nutritional genomics research is presented.

Adlercreutz H, Hämäläinen E, Gorbach SL, Goldin BR, Woods MN, Dwyer JT. Am J Clin Nutr. 1989 Mar;49(3):433-42

We studied 27 postmenopausal women, 9 vegetarians, 10 omnivores, and 8 apparently healthy women with breast cancer (BC), four times during 1 y. Dietary intakes were recorded and plasma androgens and sex-hormone-binding globulin (SHBG) binding capacity were determined. Androstenedione (A), testosterone (T), free T (FT), and SHBG were higher in omnivores than in vegetarians. In multiple correlation analysis, intakes of protein and fat were positively correlated with A, T, and FT, whereas the intakes of carbohydrate, grain, total fiber, and grain fiber showed the opposite correlations. Protein intake was positively correlated with percentage FT (%FT) and negatively with SHBG. BC patients had a similar pattern to omnivores with even higher levels of A and T (significant compared with vegetarians) and they showed significantly higher FT and lower SHBG than both control groups. We conclude that a Western-type diet in postmenopausal women is associated with high A, T, %FT, FT, and low SHBG and this pattern was apparent in the BC patients.

Goldin BR, Adlercreutz H, Dwyer JT, Swenson L, Warram JH, Gorbach SL. Cancer Res. 1981 Sep;41(9 Pt 2):3771-3

Fecal, urinary, and plasma estrogens and plasma androgens were studied in healthy pre- and postmenopausal vegetarian and omnivorous women. Dietary histories of the subjects revealed that omnivores consumed a higher percentage of total protein and fat from animal sources. The total 72-hr fecal excretion as measured by dry weight was higher for vegetarians. Preliminary results indicate that vegetarian women excrete 2 to 3 times more estrogens in feces than do omnivores and that omnivores have about 50% higher mean plasma level of unconjugated estrone and estradiol than vegetarians. Estriol-3-glucuronide, a compound that is formed upon reabsorption of free estriol from the intestine, is found in lower concentrations in the urine of vegetarians. These data suggest that in vegetarians a greater amount of the biliary estrogens escape reabsorption and are excreted with the feces. The differences in estrogen metabolism may explain the lower incidence of breast cancer in vegetarian women.

Phinney SD, Odin RS, Johnson SB, Holman RT, Am J Clin Nutr. 1990 Mar;51(3):385-92

Lipid fractions such as phospholipids (PLs), cholesteryl esters (CEs), and free fatty acids (FFAs) represent source pools for eicosanoid synthesis. To determine whether dietary habits affect the enrichment of 20:4n-6 in these precursor pools, we studied humans with partial or complete arachidonate restriction resulting from chronic avoidance of animal fat and tissue. Fasting serum was obtained from omnivorous control subjects (Omni, n = 100), semivegetarians (Semiveg, n = 16), and vegetarians (Veg, n = 25). PLs, CEs, FFAs, and triglyceride (TG) fatty acids were quantitated by thin-layer and gas chromatography. Serum 20:4n-6 was lower in the PL fraction in both Veg (p less than 0.01) and Semiveg groups (p less than 0.05) than in the Omni group and lower in the CE fraction in the Veg group (p less than 0.05). Serum 18:2n-6 did not differ between groups for any serum lipid fraction. 18:3n-3 was elevated in PLs and CEs of both Veg (p less than 0.05 and 0.01) and Semiveg groups (p less than 0.05 and 0.01) compared with the Omni group but did not result in differences in 20:5n-3 in PLs or CEs between diet groups. The lower concentration of 20:4n-6 in serum PLs and CEs of the Veg group indicates that dietary arachidonic acid enriches its circulating pool in humans; however, 20:5n-3 is not similarly responsive to dietary restriction