AJCN October, 2009 – SUMMARY – The Triage Theory of Bruce Ames explains a likely reason for the epidemic of heart disease and cancer. It is explained more completely in the SYNPOSES at this link [http://campus.beloit.edu/nutrition/aln/1009ajcn]. And if you have questions, please ask Roc at ordman@beloit.edu. To be removed from or add someone to receive this nutrition summary, click here.
BIG NEWS 1. Vitamin K and TRIAGE theory from Bruce Ames – His data explain why you may survive short-term deficiencies for a while, but long term they will kill you. Vitamin K is the latest where a dose much greater than the daily value is essential to long term health.
WEIGHT CONTROL 2. Melatonin supplements may aid weight loss 3. Exercise may modify gene expression to prevent obesity – physical activity is able to modify the action of the genes responsible for predisposition to obesity. 4. Sweet drinks at age 5 predict future obesity – early intake of sweetened beverages predicts adiposity and weight status across childhood and adolescence. 5. How weight loss without exercise can cause weight gain – Bodily organs use less energy.
6. Choline [in eggs] reduces anxiety
7. High fiber intake may prevent pregnancy
INTERESTING 8. Vegetarians have bones almost like meat eaters 9. How exercise helps weight loss – an increase in the overall drive to eat but a decrease in food needed to get full. 10. Basis for successful weight loss sought – aspects of brain activation in response to food-related visual stimuli distinguish SWLs from obese persons who fail to maintain any weight loss that they may have achieved. 11. Seven Obesity genes being identified 12. Dairy effect on weight is unclear 13. Pregnant women need iron 14. High protein diet blunts fat effect
15. Mercury in some fish is hazardous – But canned tuna is swell. Mothers consuming ≥2 portions/wk of canned tuna had newborns who weighed more than those who consumed <1 portion/mo.
DETAILS –
1. Vitamin K from Bruce Ames – The triage theory posits that some functions of micronutrients (the {approx}40 essential vitamins, minerals, fatty acids, and amino acids) are restricted during shortage and that functions required for short-term survival take precedence over those that are less essential. Insidious changes accumulate as a consequence of restriction, which increases the risk of diseases of aging. For 16 known vitamin K–dependent (VKD) proteins, we evaluated the relative lethality of 11 known mouse knockout mutants to categorize essentiality…Genetic loss of less critical VKD proteins, dietary vitamin K inadequacy, human polymorphisms or mutations, and vitamin K deficiency induced by chronic anticoagulant (warfarin/coumadin) therapy are all linked to age-associated conditions: bone fragility after estrogen loss (osteocalcin) and arterial calcification linked to cardiovascular disease (Mgp). There is increased spontaneous cancer in Tgfbi mouse knockouts, and knockdown of Tgfbi causes mitotic spindle abnormalities. A triage perspective reinforces recommendations of some experts that much of the population and warfarin/coumadin patients may not receive sufficient vitamin K for optimal function of VKD proteins that are important to maintain long-term health.
2. Melatonin supplements may aid weight loss – Background: Age and certain lifestyle factors, including a higher body mass index and exposure to light at night, are related to lower circulating concentrations of melatonin—a hormone with probable cancer-protective properties. Although melatonin is a direct derivative of the essential amino acid tryptophan, little is known about the relation of diet with melatonin concentrations…Conclusion: Although no specific nutrients were associated with altered concentrations of melatonin, our findings raise the possibility that several specific foods, including red meat, could affect cancer risk through the lowering of melatonin concentrations.
3. Exercise may modify gene expression to prevent obesity – Background: The development of obesity is still a poorly understood process that is dependent on both genetic and environmental factors.Conclusions: Our results suggest that, in physically active individuals, the genetic variation in weight is reduced, which possibly suggests that physical activity is able to modify the action of the genes responsible for predisposition to obesity, whereas the protein content of the diet has no appreciable effect.
4. Sweet drinks at age 5 predict future obesity – girls were categorized as consuming <1, ≥1 and <2, or ≥2 servings of sweetened beverages…Results: Sweetened beverage intake at age 5 y, but not milk or fruit juice intake, was positively associated with adiposity from age 5 to 15 y. Conclusion: These findings provide new longitudinal evidence that early intake of sweetened beverages predicts adiposity and weight status across childhood and adolescence.
5. How weight loss without exercise can cause weight gain – Background: Weight loss leads to reduced resting energy expenditure (REE) independent of fat-free mass (FFM) and fat mass (FM) loss, but the effect of changes in FFM composition is unclear…Results: Weight loss was 9.5 ± 3.4 kg…Decreases in REE (–8%), free triiodothyronine concentrations (–8%), muscle (–3%), heart (–5%), liver (–4%), and kidney mass (–6%) were observed .
6. Choline [in eggs] reduces anxiety – Background: Despite its importance in the central nervous system as a precursor for acetylcholine and membrane phosphatidylcholine, the role of choline in mental illness has been little studied…Results: The lowest choline quintile was significantly associated with high anxiety levels (odds ratio: 1.33). Conclusion: In this large population–based study, choline concentrations were negatively associated with anxiety symptoms but not with depression symptoms.
7. High fiber intake may prevent pregnancy – Conclusions: These findings suggest that a diet high in fiber is significantly associated with decreased hormone concentrations and a higher probability of anovulation.
8. Vegetarians have bones almost like meat eaters – A recent 2009 survey suggests that {approx}3.2% of US adults adhere to a vegetarian-based diet and {approx}0.5% of US adults consume no animal products at all (1). Similar 2009 figures have also been published for the United Kingdom ({approx}3% are completely vegetarian) (2). Given that we are now in an epidemic of osteoporosis, with >10 million Americans affected and with estimated costs in the United States and Europe rising above $17.9 billion and {euro}13.9 billion annually, respectively, we need conclusive evidence on how exogenous (modifiable) factors can significantly improve (or harm) bone health at the population level (4). overall, bone density was lower in those subjects who adhered to a vegetarian/vegan diet than in those who consumed an omnivorous one but at a level that is unlikely to be clinically relevant.
9. How exercise helps weight loss – Conclusions: These data show that the effect of exercise on appetite regulation involves at least 2 processes: an increase in the overall (orexigenic) drive to eat and a concomitant increase in the satiating efficiency of a fixed meal.
10. Basis for successful weight loss sought – As the prevalence of obesity continues to rise in many countries and an increasing number of people attempt to lose weight, there is an increasing urgency for the identification of strategies to achieve successful, long-term maintenance of weight loss. Most therapeutic trials of drugs or dietary approaches can show mean weight losses of {approx}10% over a 6-mo period, which can then be sustained for ≤2 y, but the range of weight loss and of longer-term success varies markedly within the groups studied, and little information is available to explain this variability. The US National Weight Control Registry has been gathering information for >15 y on persons who are successful in maintaining weight loss and has shown that those who are successful at maintaining weight loss (successful weight-loss maintainers; SWLs) work harder to limit their food intake and increase their physical activity than do those who fail to maintain their weight loss (1). The article by McCaffery et al (2) in this issue of the Journal seeks to identify aspects of brain activation in response to food-related visual stimuli that distinguish SWLs from obese persons who fail to maintain any weight loss that they may have achieved.
11. Obesity genes being identified – Background: New genetic loci, most of which are expressed in the brain, have recently been reported to contribute to the development of obesity. The brain, especially the hypothalamus, is strongly involved in regulating weight and food intake.Results: Seven SNPs were associated (P < 0.05) with weight, body mass index (BMI), and waist circumference .
12. Dairy effect on weight is unclear – The milk group was instructed to consume 3–5 portions of dairy products daily. The control group maintained their habitual diet.Among participants with a low calcium intake at baseline (<700 mg/d), there was a significant treatment effect for waist circumference…Conclusions: This study gives no clear support to the hypothesis that a moderately increased intake of dairy products beneficially affects aspects of the metabolic syndrome.
13. Pregnant women need iron – Background: For many pregnant Canadian women, usual iron intakes from food appear to be inadequate compared with Dietary Reference Intake requirement estimates…Conclusions: On the basis of Dietary Reference Intakes, an iron supplement of 16 mg/d throughout pregnancy is justified as both efficacious and safe for healthy women living in Canadian households. [Dietary meat intake in US may be much higher.]
14. High protein diet blunts fat effect – Background: High sugar and fat intakes are known to increase intrahepatocellular lipids (IHCLs) and to cause insulin resistance. High protein intake may facilitate weight loss and improve glucose homeostasis in insulin-resistant patients, but its effects on IHCLs remain unknown.Conclusions: Protein intake significantly blunts the effects of an HF diet.
15. Mercury in some fish is hazardous – Results: …newborns in the higher quartile of total mercury weighed 143.7 g less and had higher odds of being small for gestational age (SGA) for length compared with those in the lowest quartile. Mothers consuming ≥2 portions/wk of canned tuna had newborns who weighed more than those who consumed <1 portion/mo. Consumption of ≥2 portions/wk of large oily fish was associated with a higher risk of being SGA for weight and consumption of lean fish with a lower risk of being SGA for length compared with the consumption of <1 portion/mo.
“The academy is not paradise. But learning is a place where paradise can be created. The classroom with all its limitations remains a location of possibility. In that field of possibility we have the opportunity to labour for freedom, to demand of ourselves and our comrades, an openness of mind and heart that allows us to face reality even as we collectively imagine ways to move beyond boundaries, to transgress. This is education as the practice of freedom.” — Bell Hooks
