Nutrition

AJCN May, 2007

[carbs control genes ] Putting your genes on a diet: the molecular effects of carbohydrate ” Traditionally, food is thought to influence human health through its nutrient content, whereas drugs are recognized to act through molecular pathways. However, consumption of a meal stimulates the release of numerous hormones that can powerfully affect signal transduction and gene function. .. The study by Kallio et al makes a significant contribution to the literature by demonstrating the potentially major effects of dietary composition on gene regulation, independent of energy intake and body weight. Two specific findings concerning the low-insulin-response diet merit particular attention: the down-regulation of both hormone-sensitive lipase (HSL) and TCF7L2.”

[1% are sensitive to histamines]Histamine and histamine intolerance “[1% of the population has histramine intolerance.] In healthy persons, dietary histamine can be rapidly detoxified by amine oxidases, whereas persons with low amine oxidase activity are at risk of histamine toxicity…The ingestion of histamine-rich food or of alcohol or drugs that release histamine or block DAO may provoke diarrhea, headache, rhinoconjunctival symptoms, asthma, hypotension, arrhythmia, urticaria, pruritus, flushing, and other conditions in patients with histamine intolerance. Symptoms can be reduced by a histamine-free diet or be eliminated by antihistamines. ”

[CLAs reduce fat]Efficacy of conjugated linoleic acid for reducing fat mass: a meta-analysis in humans “Conjugated linoleic acid (CLA) has been shown to be an effective supplement for reducing fat mass in animals, whereas results in humans have been inconsistent…This comparison indicated that the effect of CLA was linear for up to 6 mo and then slowly approached an asymptote at 2 y…Given at a dose of 3.2 g/d, CLA produces a modest loss in body fat in humans.”

[Low energy density diet aids weight loss] Reductions in dietary energy density are associated with weight loss in overweight and obese participants in the PREMIER trial ” Dietary energy density (ED) reductions are associated with energy intake (EI) reductions. Little is known about influences on body weight (BW)…the established group received an 18-session intervention implementing well-established hypertension recommendations (eg, weight loss, sodium reduction, and physical activity), the established+Dietary Approaches to Stop Hypertension (DASH) group received an 18-session intervention also implementing the DASH diet, and the advice group received 1 session on these topics…Results:Each group had significant declines in EI, ED, and BW. The established and established+DASH groups had the greatest EI and BW reductions.”

[fishoil helps heart; flax and olive oil cannot substitute] Effects of fish-oil supplementation on myocardial fatty acids in humans ” The study examined the kinetics of incorporation of n–3 fatty acids into human myocardial membrane phospholipids during supplementation with fish oil and -linolenic acid–rich flaxseed oil…In the fish-oil-treated subjects, accumulation of EPA and DHA in the right atrium was curvilinear with time and reached a maximum at 30 d of treatment and displaced mainly arachidonic acid. Flaxseed oil supplementation yielded a small increase in atrial EPA but not DHA, whereas olive oil did not significantly change atrial n–3 fatty acids. Conclusion: The results of the present study show that dietary n–3 fatty acids are rapidly incorporated into human myocardial phospholipids at the expense of arachidonic acid [which contributes to inflammation] during high-dose fish-oil supplementation.[see table of composition of olive, flaxseed, and fish oil.]

[Boiled/steamed healthier than fried/grilled] Effects of low- and high-advanced glycation endproduct meals on macro- and microvascular endothelial function and oxidative stress in patients with type 2 diabetes mellitus ” Background: An advanced glycation endproducts (AGEs)–rich diet induces significant increases in inflammatory and endothelial dysfunction markers in type 2 diabetes mellitus (T2DM). ..a High AGE meal [fried/grilled] induces a more pronounced acute impairment of vascular function than does an otherwise identical Low AGE meal [steamed/boiled]. Therefore, chemical modifications of food by means of cooking play a major role in influencing the extent of postprandial vascular dysfunction.

[Olive oil lowers blood pressure more than carbs-choose proper salad dressing] Effect of high-carbohydrate or high-cis-monounsaturated fat diets on blood pressure: a meta-analysis of intervention trials “The Dietary Approaches to Stop Hypertension (DASH) diet is recommended to manage blood pressure. The DASH diet is low in saturated fat, but it is not clear whether saturated fat should be preferentially replaced with carbohydrate or unsaturated fat, especially cis-monounsaturated fat…Diets rich in carbohydrate may be associated with slightly higher blood pressure than diets rich in cis-monounsaturated fat.”

[fish oil and exercise together are best] Combining fish-oil supplements with regular aerobic exercise improves body composition and cardiovascular disease risk factors “Regular exercise and consuming long-chain n–3 fatty acids (FAs) from fish or fish oil can independently improve cardiovascular and metabolic health, but combining these lifestyle modifications may be more effective than either treatment alone… Fish Oil supplements and regular exercise both reduce body fat and improve cardiovascular and metabolic health. Increasing intake of n–3 FAs could be a useful adjunct to exercise programs aimed at improving body composition and decreasing cardiovascular disease risk.

[Eat plenty of eggs for choline, esp. for brain health ] Sex and menopausal status influence human dietary requirements for the nutrient choline “Although humans require dietary choline for methyl donation, membrane function, and neurotransmission, choline can also be derived from the de novo synthesis of phosphatidylcholine, which is up-regulated by estrogen. A recommended Adequate Intake (AI) exists for choline [450 mg – though 850 mg may be much better]When deprived of dietary choline, 77% of men and 80% of postmenopausal women developed fatty liver or muscle damage, whereas only 44% of premenopausal women developed such signs of organ dysfunction. Moreover, 6 men developed these signs while consuming 550 mg choline · 70 kg–1 · d–1, the AI for choline. Folic acid supplementation did not alter the subjects’ response. Conclusion: Subject characteristics (eg, menopausal status) modulated the dietary requirement for choline, and a daily intake at the current AI was not sufficient to prevent organ dysfunction in 19 of the [57] subjects.

[People 55 and older must eat 1.2g protein per kg body weight per day to maintain muscle] Inadequate protein intake affects skeletal muscle transcript profiles in older humans “Inadequate dietary protein intake causes adverse changes in the morphology and function of skeletal muscle…Twenty-one older men and women (aged 55–80 y) consumed…either 0.5 g protein · kg–1 · d–1 [inadequate protein (IP) group] or 1.2 g protein · kg–1 · d–1 (control group) … Conclusion: The results document changes in skeletal muscle transcript levels induced by short-term inadequate protein intakes in older humans that might precede adverse metabolic, functional, and structural events, including muscle wasting.

[whole grain stops colon cancer better than fiber] Dietary fiber and whole-grain consumption in relation to colorectal cancer in the NIH-AARP Diet and Health Study “The objective was to investigate the relation between dietary fiber and whole-grain food intakes and invasive colorectal cancer in the prospective National Institutes of Health–AARP Diet and Health Study…Conclusions: In this large prospective cohort study, total dietary fiber intake was not associated with colorectal cancer risk, whereas whole-grain consumption was associated with a modest reduced risk.”

[fish oil and folate from gestation week 22 necessary for optimum health] Effects of fish-oil and folate supplementation of pregnant women on maternal and fetal plasma concentrations of docosahexaenoic acid and eicosapentaenoic acid: a European randomized multicenter trial “Pregnant women usually meet their increased energy needs but do not always meet their increased micronutrient requirements. The supply of both folic acid and docosahexaenoic acid (DHA) has been related to positive pregnancy and infant outcomes…Conclusions: FO supplementation from gestation week 22 until delivery improves fetal n–3 LC-PUFA status and attenuates depletion of maternal stores. MTHF may further enhance maternal n–3 LC-PUFA proportions.”

[high meat diet increases skin cancer risk up to 4-fold] Dietary pattern in association with squamous cell carcinoma of the skin: a prospective study “The meat and fat pattern was positively associated with development of SCC tumors (RR = 1.83…) after adjustment for confounders and even more strongly associated in participants with a skin cancer history (RR = 3.77…) A dietary pattern characterized by high meat and fat intakes increases SCC tumor risk, particularly in persons with a skin cancer history.

[need folate supplements even after fortified diet in US] Race-ethnicity differences in folic acid intake in women of childbearing age in the United States after folic acid fortification: findings from the National Health and Nutrition Examination Survey, 2001–2002 “Background: Neural tube defects are serious birth defects of the brain and spinal cord. Up to 70% of neural tube defects can be prevented by the consumption of folic acid by women before and early during pregnancy…Conclusions: Most nonpregnant women of childbearing age in the United States reported consuming less than the recommended amount of folic acid. The proportion with low daily folic acid intake was significantly higher in non-Hispanic black and Hispanic women than in non-Hispanic white women. At the present level of folic acid fortification, most women need to take a folic acid–containing dietary supplement to achieve the Institute of Medicine recommendation.”

[low glycemic index meal promotes better gene expression than high GI meal] Dietary carbohydrate modification induces alterations in gene expression in abdominal subcutaneous adipose tissue in persons with the metabolic syndrome: the FUNGENUT Study “Conclusions: Dietary carbohydrate modification with rye and pasta [low GI meal] or oat, wheat, and potato [high GI meal] differentially modulates the gene expression profile in abdominal subcutaneous adipose tissue, even in the absence of weight loss.

[calcium foods better than supplements for bones]Effects of dietary calcium compared with calcium supplements on estrogen metabolism and bone mineral density ” the role of dietary calcium and calcium supplements on estrogen metabolism and BMD remains unknown. Conclusion: Calcium from dietary sources is associated with a shift in estrogen metabolism toward the active 16-hydroxyl metabolic pathway and with greater BMD and thus may produce more favorable effects in bone health in postmenopausal women than will calcium from supplements.”