PERSONAL COMMENT: I am honored that so many people around the world have asked to receive my summaries of the latest peer-reviewed nutrition research. Having studied nutrition for many decades, I recognize that my summaries often reflect my scientific prejudices. Please read the brief article about the likely benefit of vitamin C and E supplements for telomere length and human health to see how heavily my beliefs may influence Nutrition Investigator notes. Going to professional meetings, I recognize my beliefs are debatable by others. You must read the articles at the links and discuss these comments with your health professional before acting on this information, as noted in the site disclaimer. And you are encouraged to ask questions, through the link at Site Author at the top of each page. One goal of these messages is to help you be conscious of what you put in your body. Thank you for the many kind responses and insightful questions I receive in return.
AJCN June, 2009 – SUMMARY
FEATURE THIS MONTH 1.Vitamin C and E probably preserve telomere length (and thus health) – Replicating human somatic cells display progressive telomere shortening (LTL). Ultimately, such cells either undergo apoptosis or enter a state of replicative senescence that is triggered by critically shortened telomeres. .. Cigarette smokers, obese and sedentary individuals, and those with unhealthy habits in general often exhibit not only increases in the systemic burden of oxidative stress and inflammation but also shortened telomeres. …women with higher intakes of vitamins C and E, or taking multivitamins, showed a longer LTL…It follows that the habitual ingestion of vitamin C and E supplements and/or multivitamins somehow “slows down” the rate of age-dependent telomere shortening…
FOR EVERYONE
2. 500 mcg Vitamin K daily substantially reduces heart attack risk
3. Iron excretion varies 40-fold in people
4. Stronger cocoa is better
5. Selenium supplements not useful
6. Dairy diet reduces hypertension
7. Meat and how it’s cooked contribute to cancer
8. High salt diet does not cause inflammation
9. Soy reduces breast cancer risk
OBESITY 10. Just 100 to 400 extra Cal/day is causing obesity epidemic
11. Eat nuts to get thinner – incorporating nuts may help weight control.
12. High fructose intake causes liver and muscle damage
FOR PARENTS 13. Lower protein intake in infancy might diminish the later risk of overweight and obesity. Editorial: Formula for bottle feeding may cause infant obesity
14. Low carb diet useful for weight loss when nursing
15. Teens are eating more than they say
INTERNATIONAL NUTRITION STUDIES – India Golden Rice Bangladesh East and Southest Asia Puerto Rico Shanghai
SYMPOSIUM ON BIOMARKERS OF MICRONUTRIENT STATUS – research on how effectively your nutrition status can be determined
My organic garden is doing wonderfully this year. Here is a thought from Thich Nhat Hahn: People deal too much with the negative, with what is wrong. Why not try and see positive things, to just touch those things and make them bloom?
DETAILS –1.Vitamin C and E probably preserve telomere length – In culture, replicating human somatic cells display progressive telomere shortening. Ultimately, such cells either undergo apoptosis or enter a state of replicative senescence that is triggered by critically shortened telomeres. Accordingly, telomere length is an index of both the replicative history and the replicative potential of human somatic cells in culture (1). Most replicating human somatic cells undergo telomere shortening in vivo. In addition, leukocyte telomere length (LTL) is associated with aging-related disorders, principally atherosclerosis (2). .. the co-twins with the shorter LTL were more likely to die first (3, 4). These observations support the proposition that LTL is a biomarker of human aging…LTL is heritable but modified by a host of environmental variables. Cigarette smokers, obese and sedentary individuals, and those with unhealthy habits in general often exhibit not only increases in the systemic burden of oxidative stress and inflammation but also shortened LTL. Telomeres are highly sensitive to the hydroxyl radical, which causes DNA breakage (7). Consequently, increased free radical concentrations might cause the clipping of greater stretches of telomeres with each replication of HSCs. Inflammation would increase the rate of HSC replication to accommodate the increased demand for leukocytes due to their engagement in the inflammatory process. In short, a chronic increase in the systemic burden of oxidative stress and inflammation enhances the rate of telomere shortening in HSCs, which is ultimately expressed in shortened LTL…women with higher intakes of vitamins C and E, which were estimated on the basis of food intake questionnaires, also showed a longer LTL…It follows that the habitual ingestion of multivitamins somehow “slows down” the rate of age-dependent telomere shortening in HSCs. On the basis of theoretical considerations, the reduction in systemic burdens of oxidative stress, inflammation, or both might exert such an effect, although the notion that vitamin supplements are able to accomplish such a reduction will surely generate a provocative debate…A number of studies have implicated increased systemic iron burdens in coronary heart disease. Multivitamin use also preserves telomeres.
2. 500 mcg Vitamin K daily substantially reduces heart attack risk – Background: Coronary artery calcification (CAC) is an independent predictor of cardiovascular disease. A preventive role for vitamin K in CAC progression has been proposed on the basis of the properties of matrix Gla protein (MGP) as a vitamin K–dependent calcification inhibitor… [Subjects] received a multivitamin with 500 µg phylloquinone/d …Conclusions: Phylloquinone supplementation slows the progression of CAC in healthy older adults with preexisting CAC, independent of its effect on total MGP concentrations.
3. Iron excretion varies 40-fold in people – Conclusions: The results extend direct iron excretion measurements in men to include similar measurements in women. The results emphasize the wide range of iron excretion in humans, which results in a 40-fold range of requirements for absorbed iron.
4. Stronger cocoa is better – Background: Cocoa drinks containing flavan-3-ols are associated with many health benefits…Whether similar protective effects are associated with the consumption of many commercial chocolate and cocoa products containing substantially lower amounts of flavan-3-ols, especially when absorption at lower doses is obstructed by milk, remains to be determined.
5. Selenium supplements not useful – Conclusions: Selenium supplementation produced no clinically significant changes in thyroid hormone concentrations.
6. Dairy diet reduces hypertension – Conclusion: Intake of low-fat dairy products may contribute to the prevention of hypertension at an older age.
7. Meat and how it’s cooked contribute to cancer – Conclusion: We observed a moderate association between meat consumption and lung carcinoma, which might be explained by heme iron intake, high-temperature cooking, and associated mutagens.
8. High salt diet does not cause inflammation – Conclusions: We observed a linear association between an objective measure of sodium intake and serum CRP that may be influenced by confounding by body mass index. The magnitude of these associations suggests that dietary sodium consumption is unlikely to be an important modifiable risk factor for increased systemic inflammation.
9. Soy reduces breast cancer risk – Conclusion: This large, population-based, prospective cohort study provides strong evidence of a protective effect of soy food intake against premenopausal breast cancer.
10. Just 100 to 400 extra Cal/day is causing obesity epidemic – body mass largely reflects a mix of water and energy-yielding organic chemicals, and when considered as a thermodynamic system, stores can only increase when substrate intake exceeds losses. Agreement, however, stops beyond this simple conjecture…assumptions: an energy content of weight change of 3500 kcal/lb …Hill et al concluded that adult population weight gain could be eliminated by a combination of reducing intake and increasing energy expenditure by {approx}100 kcal/d…Swinburn et al’s estimated energy gap that accounts for US population weight gain since the 1970s is several-fold higher ({approx}400 kcal/d) than that originally proposed by Hill et al ({approx}100 kcal/d; 1). See main article.
11. Eat nuts to get thinner – Conclusions: …in healthy middle-aged women… The results suggest that incorporating nuts into diets does not lead to greater weight gain and may help weight control.
12. High fructose intake causes liver and muscle damage – Background: Both nutritional and genetic factors are involved in the pathogenesis of nonalcoholic fatty liver disease and insulin resistance…Conclusions: A 7-d high-fructose diet increased ectopic lipid deposition in liver and muscle and fasting VLDL-triacylglycerols and decreased hepatic insulin sensitivity.
13. Lower protein intake in infancy might diminish the later risk of overweight and obesity. Editorial: Formula for bottle feeding may cause infant obesity – The daily protein requirement and optimal protein intake in healthy full-term infants and the protein-energy ratio, safety, and long-term consequences of infant milk formula have been the subject of numerous deliberations over the past 50 y. ..significant gaps in our knowledge persist…The authors have examined the effect of lower and higher protein intake (within the recommended range) during the first 12 mo (infancy) on the growth pattern of infants until 24 mo of age…The weight-for-length at 24 mo was lower in the infants fed lower protein formula and was not different from the breastfed reference group. [Most current formulae use the higher protein formula.]
14. Low carb diet useful for weight loss when nursing – Background: No evidence-based recommendations exist concerning what dietary macronutrient composition optimizes weight loss during lactation while maintaining milk production. Objectives: The study was designed to test the following hypotheses: compared with a reduced-calorie, high-carbohydrate (H-CHO) diet, an isonitrogenous, isocaloric high-fat (H-F) diet will decrease milk production and carbohydrate oxidation, increase gluconeogenesis and hexoneogenesis, and not affect energy balance. Conclusions: Milk fat, energy output, and energy expenditure were higher during the H-F diet, which resulted in a greater negative energy balance. The lactating mothers adapted to a low carbohydrate intake by decreasing carbohydrate oxidation.
15. Teens are eating more than they say – Conclusions: The increased underreporting of dietary intake with increasing body weight in teens may explain in part previous reports noting that there has been an increased incidence of obesity, although energy intakes have not appeared to increase.
INTERNATIONAL NUTRITION STUDIES – More people around the world are reading nutrition investigator columns like this one. There is plenty of attention nutrition research about non-Western nations. Here are some of the places where studies are reported this month. India Golden Rice Bangladesh East and Southest Asia Puerto Rico Shanghai
SYMPOSIUM ON BIOMARKERS OF MICRONUTRIENT STATUS – research on how effectively your nutrition status can be determined
Background: To explore the relation between micronutrient status and health, it is important to understand which markers of micronutrient status can be relied on and under what circumstances. Objective: The objective of this article was to develop a common systematic review methodology for use in the assessment of micronutrient status for selenium, iodine, copper, zinc, riboflavin, vitamin B-12, vitamin D, and omega-3 (n–3) long-chain polyunsaturated fatty acids.
vitamin B-12 – Conclusions: The available evidence suggests that plasma and serum concentrations of total vitamin B-12, methylmalonic acid, and total homocysteine are all effective biomarkers of a change in vitamin B-12 intake; however, because the available data were limited, it was not possible to examine fully the factors that could explain the substantial heterogeneity in total vitamin B-12.
selenium – Although there is a substantial body of data for plasma selenium, more large, high-quality, randomized controlled trials are needed for this biomarker, as well as for the other biomarkers, to explore the reasons for heterogeneity in response to selenium supplementation.
iodine – Conclusions: Despite the high risk of bias of many of the included studies, the results suggested that urinary iodine, thyroglobin, serum thyroxine, and thyroid-stimulating hormone are useful biomarkers of iodine status, at least in some groups.
copper – Conclusions: Despite limited data, serum copper appears to be a useful biomarker of copper status at the population level.
zinc – Conclusions: This systematic review confirms that in healthy individuals, plasma, urinary, and hair zinc are reliable biomarkers of zinc status. Further high-quality studies using these biomarkers are required, particularly in infants, adolescents, and immigrant population groups for whom there are limited data.
riboflavin –
vitamin D – Conclusions: This systematic review confirmed that circulating 25(OH)D is a robust and reliable marker of vitamin D status.
omega-3 (n–3) long-chain polyunsaturated fatty acids – There were sufficient data to determine that plasma DHA, plasma phospholipid DHA, plasma triacylglycerol DHA, plasma cholesteryl ester DHA, plasma nonesterified DHA, erythrocyte DHA, erythrocyte phospholipid DHA, and platelet DHA were all effective biomarkers of DHA status and that plasma phospholipid EPA was an effective marker of EPA status. ..Conclusion: There appears to be a range of useful biomarkers of DHA status in humans…
