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The Nutrition InvestigatorThe health and nutrition blog by Dr. Roc Ordman.

July Sept Advances in Nutrition long notes from Roc

by Roc (click here for full post)

Highlights from Advances in Nutrition, July and Sept issues

Older adults need more vitamin E (consider AREDS). We review the evidence that was considered in establishing the current requirements for vitamin E and highlight data that should be considered in determining the vitamin E requirements in older adults, particularly focusing on the evidence suggesting a benefit of increased vitamin E intake on immune function and inflammatory processes and resistance to infection. The main objective of this Perspective is to initiate the discussion of whether the current Dietary Reference Intake for vitamin E should be increased for the older population. We make this suggestion on the basis of mechanistic studies showing biological plausibility, correction of a major cellular dysfunction in older adults, and strong evidence from several animal and a few human studies indicating a reduction in risk and morbidity from infections.

A 2013 nationally representative phone survey of about 2000 subjects showed that one-fifth of Americans thought fast food (FF) was good for health, whereas two-thirds considered FF not good. Even over two-thirds of weekly FF consumers (47% of the total population) thought FF not good. Americans seem to have limited knowledge of calories in FF. Negative and positive FF perceptions were associated with FF consumption. Those who consumed less FF seemed more likely to view FF negatively.

Children with autism spectrum disorder (ASD) are 4 times as likely to experience gastrointestinal symptoms as children without ASD. The gut microbiota has increasingly been the subject of investigation as a contributing factor to these symptoms in this population because there is evidence to suggest that alterations in the intestinal microflora are correlated with gastrointestinal and ASD symptom severity.  There is promising evidence to suggest that probiotic therapy may improve gastrointestinal dysfunction, beneficially alter fecal microbiota, and reduce the severity of ASD symptoms in children with ASD.

Dietary choices contribute to inflammation which causes specific cancers, esp. colon, pancreatic, and esophagus. Existing evidence suggests a link between the inflammatory potential of diet and risk of cancer. This study aimed to test the linear and potential nonlinear dose-response associations of the Dietary Inflammatory Index (DII), as being representative of inflammatory features of the diet, and site-specific cancer risk.  The pooled RRs for a 1-unit increment in the DII were as follows: colorectal cancer, 1.06 (95% CI: 1.04, 1.08; I2 = 72.5%; n = 9); breast cancer, 1.03 (95% CI: 1.00, 1.07; I2 = 84.0%; n = 7); prostate cancer, 1.06 (95% CI: 0.97, 1.15; I2 = 56.2%; n = 6); pancreatic cancer, 1.16 (95% CI: 1.05, 1.28; I2 = 61.6%; n = 2); ovarian cancer, 1.08 (95% CI: 1.03, 1.13; I2 = 0%; n = 2); esophageal squamous cell carcinoma, 1.24 (95% CI: 1.10, 1.38; I2 = 64.3%; n = 2); renal cell carcinoma, 1.08 (95% CI: 1.02, 1.13; I2 = 0%; n = 2); and esophageal adenocarcinoma, 1.26 (95% CI: 1.13, 1.39; I2 = 0%; n = 2). A nonlinear dose-response meta-analysis showed that, after a somewhat unchanged risk within initial scores of the DII, the risk of colorectal cancer increased linearly with increasing DII score. In the analyses of breast and prostate cancers, the risk increased with a very slight trend with increasing DII score. In conclusion, the results showed that dietary habits with high inflammatory features might increase the risk of site-specific cancers.

Higher protein intake is safe. The evidence from the current review is limited and inconsistent with regard to the role of protein intake and the risk of kidney stones. Increased protein intake had little or no effect on blood markers of kidney function. Evidence reported here suggests that protein intake above the US RDA has no adverse effect on blood pressure. All included studies were of moderate to high risk of bias and, with the exception of 2 included cohorts, were limited in duration (i.e. <6 mo). Data in the current review are insufficient to determine if increased protein intake from a particular source, i.e., plant or animal, influences kidney health outcomes. These data further indicate that, at least in the short term, higher protein intake within the range of recommended intakes for protein is consistent with normal kidney function in healthy individuals.

Caffeine reduces risk of kidney stones.  Caffeine is one of the main components in caffeinated beverages worldwide (i.e., coffee, tea, soft drinks, and energy drinks). Previous retrospective and prospective studies have reported contradictory effects of caffeine on kidney stone risk. Although it has a diuretic effect on enhancing urinary output, it may slightly increase the stone risk index. However, 3 large cohorts have suggested a preventive role of caffeine in kidney stone disease.

Homeostasis of nutrient metabolism is critical for maintenance of the normal physiologic status of the cell and the integral health of humans and mammals. In vivo, there is a highly efficient and precise process involved in nutrient recycling and organelle cleaning. This process is named autophagy, and it can be induced in response to the dynamic change of nutrients. When cells face nutritional stress, such as stress caused by nutrient deficiency or nutrient excess, the autophagy pathway will be activated. Generally, when nutrients are withdrawn, cells will sense the signs of starvation and respond. AMP-activated protein kinase and the mammalian target of rapamycin, two of the major metabolic kinases, are responsible for monitoring cellular energy and the concentration of amino acids, respectively. Nutrient excess also induces autophagy, mainly via the reactive oxygen species and endoplasmic reticulum stress pathway. When nutritional stress activates the autophagy pathway, the nutrients or damaged organelles will be recycled for cell survival. However, if autophagy is overwhelmingly induced, autophagic cell death will possibly occur.

An individual’s micronutrient status can be affected by a wide range of factors, including habitual diet, medications, dietary supplements, metabolic disorders, and surgery, particularly surgery involving the gastrointestinal system. This challenge is of particular concern for calcium, vitamin D, fiber, and potassium, which have been identified in the 2015–2020 US Dietary Guidelines for Americans as nutrients of public health concern because their underconsumption has been linked in the scientific literature to adverse health outcomes, as well as for sodium, which is overconsumed.

A reasonable recommendation for physicians and their patients who are taking these drugs is to monitor vitamin B-12 status and to provide vitamin B-12 supplements if altered blood biomarkers or clinical signs consistent with low or deficient vitamin B-12 status develop.

3-Hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) are extremely well tolerated but are associated with a range of mild-to-moderate statin-associated muscle symptoms (SAMS). Estimates of SAMS incidence vary from <1% in industry-funded clinical trials to 10–25% in nonindustry-funded clinical trials and ∼60% in some observational studies. CoQ10 is popular as a form of adjuvant therapy for the treatment of SAMS. However, the data evaluating the efficacy of CoQ10 supplementation has been equivocal, with some, but not all, studies suggesting that CoQ10 supplementation mitigates muscular complaints.

The ability of certain foods to impair or augment the absorption of various vitamins and minerals has been recognized for many years. However, the contribution of botanical dietary supplements (BDSs) to altered micronutrient disposition has received little attention. Almost half of the US population uses some type of dietary supplement on a regular basis, with vitamin and mineral supplements constituting the majority of these products. BDS usage has also risen considerably over the last 2 decades, and a number of clinically relevant herb-drug interactions have been identified during this time. Current research indicates that certain BDSs can reduce iron, folate, and ascorbate absorption, and others contribute to heavy metal intoxication. Inhibitory effects of polyphenolics on iron absorption stem from adjacent hydroxyl and/or carbonyl groups that bind ferric iron to form chelates (17, 18). Such iron chelates are not readily absorbed across the gastrointestinal mucosa. In a recent clinical study in which subjects with metabolic syndrome were supplemented for 8 wk with a green tea BDS, plasma iron concentrations were significantly reduced, whereas copper, zinc, and selenium were not affected (27). Green tea supplementation also had no adverse effect on circulating carotenoids or tocopherols. Milk thistle (Silybum marianum), a source of flavanolignans and flavonoids collectively known as silymarin, is commonly used to treat a variety of liver and gallbladder disorders. In 2001, silibinin, a principal component of silymarin, was identified as a natural iron chelator

Phytochemical  Micronutrient affected  Effect and interaction mechanism 
Plant polyphenols (tea catechins, phloretin, quercetin) Iron Reduced absorption via complexation
  Folate, ascorbate Reduced absorption via uptake transporter inhibition
Silymarins Iron Reduced absorption via complexation
Phytic acid Calcium, iron, zinc Reduced absorption via complexation
St. John’s wort (hyperforin) Vitamin D3 Enhanced plasma clearance via induction of CYP3A4 metabolism


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