Researchers found that serum alpha-carotene concentrations were inversely correlated with risk of death (all causes, cardiovascular, cancer, and other) in over 15,000 US adults >20y. In the preamble, the authors justify their exclusive focus on alpha-carotene because of previous beta-carotene randomized control trials (RCT). Where did they ever find fruits and vegetables which didn’t contain other carotenoids? Drs S Liu and colleagues published their results online in Archives of Internal Medicine on Nov 22, 2010. They concluded that people with 9 ug/dL of alpha-carotene or more and those with 0-1 ug/dL had 39% and 23% lesser chances of early death, respectively. The authors do not report any efforts to determine the effect of beta-carotene or any other carotenoid on mortality.
Archive for 'November 2010'
Coronary artery disease is the most common type of heart disease.Not surprisingly, diet falls within the top 5 search terms on the American Heart Association website (advanced cardiovascular life support, cholesterol, cpr, diet, and heart attack).If all forms of major cardiovascular disease were eliminated, life expectancy would rise by almost 7 years. Drs PRC Howe and colleagues tested the cardioprotective potential of trans-resveratrol, a polyphenol-rich ingredient found in red wine, grape seeds, tea, and cocoa. They used a technique, flow-mediated dilation (FMD)
Vitamin D supplementation is more important during winter months when sun exposure is limited and serum 25(OH)D insufficiency may be exacerbated by genetics under these circumstances. According to a report published online in Osteoporosis International (Nov 18, 2010), four times more women are vitamin D deficient in the north of Great Britain than the south.
Last Thursday, I provided perspective on a study published in the American Journal of Clinical Nutrition citing the contribution of mandatory fortification of cereal grains and voluntary fortification in ready-to-eat breakfast cereals to folic acid intakes of American children.This week a very interesting historical summary on the history of folic acid fortification has been published
Drs L Yeung and collaborators analyzed usual daily folic intakes of 4 age-groups of children from the 2003-2006 National Health and Nutrition Examination Survey (NHANES). Since 1996, the FDA mandated that all cereal grains be fortified with 140ug folic acid/100g flour to prevent the occurrence of neural tube defects in babies as they develop during the first trimester of pregnancy. The study found that 32% of children consumed folic acid only from enriched cereal grain products. In other words, almost 1/3 of children probably wouldn’t have consumed much folic acid if the FDA hadn’t mandated folic fortification. Forty-two percent of children obtained their folic acid from fortified cereal products AND breakfast ready-to-eat cereals.
The never-ending publication of new scientific research can be overwhelming. However, it isn’t always new news! As Judy Blatman wrote in the blog for Council for Responsible Nutrition members, old studies are still very relevant. Within the past few weeks, consumers were exposed to many conflicting headlines about omega-3 fatty acids:
Last night, the New York Academy of Sciences (NYAS) held their “Science and the City” 7th Annual Gala. The NYAS is focused on ‘Developing a Scientific Agenda for Nutrition’. It was a superb evening featuring the Blavatnik Awards for Young Scientists. And an incredulous opportunity to have dinner with amazing people such as Nobel laureate, Dr James Watson. The Sackler Institute for Nutrition Science was announced.
Researchers from Johns Hopkins University reported at the American Heart Association meeting in Chicago that 32.3% of blacks and 6.65 of whites had low vitamin D levels (< 15ng/mL or 37.5 nmol/L). They had examined health records of 7,981 white and black adults from NHANES from 1988 to 1994. Adjusting for age and other risk factors, vitamin D status [serum 25(OH)D] partially explained risk of stroke death in whites but not blacks. Even though blacks were 65% more likely to suffer a stroke, more whites died of stroke than blacks (116 vs 60). Why is this?
A new prospective cohort study in 202 children under 2y admitted to intensive care in Sao Paulo Brazil reports that 28% had low blood thiamin concentrations. This study was conducted because thiamin deficiency is associated with poorer clinical outcomes in hospital. Low thiamin levels are also associated with elevated C-reactive protein concentrations (>20 ng/dl), a pro-inflammatory cytokine. The prevalence rate in young children was similar to the 33% incidence of thiamin deficiency observed in adult patients hospitalized for congestive heart failure.
In a cross-sectional study of middle-aged 1,200 Puerto Ricans (45-75y) living in the Boston area, Dr K Tucker and S Bhuparthiraju found that the variety of fruit and vegetable intakes, not the quantity consumed, was inversely associated with reduced measures of inflammation, ie lower C-reactive protein (CRP) levels. These inverse associations can be attributed to nutrients such as beta-carotene, beta-cryptoxanthin, lutein, zeaxanthin, lycopene and vitamin C. Unfortunately, median fruit and vegetable consumption was only 3.2 servings per day in this study. The NHANES survey also reported people were eating only 3.3 servings daily,
The Cholesterol Treatment Trialists’ (CTT) Collaborators published a meta-analysis of randomized controlled trials (RCT) examining the effect of more vs less intensive statin regimens with interventions of >2y on the average reduction of LDL-cholesterol (LDL-C). The authors concluded that more intensive statin therapy was superior in lowering LDL-C. They found that statin therapy reduced all-cause mortality by 10% per 1.0 mmol/L LDL reduction. They also noted similar reductions in major vascular events with no significant effect on deaths due to stroke. However, it can be seen from Figure 2 that statin therapy increases haemorrhagic stroke events (% per annum) from 57 to 63 (unweighted RR = 1.21 and weighted RR = 1.39). Compare this study and its lack of media attention to the headlines arising from the British Journal of Medicine study on vitamin E and stroke released on Nov 5.
A new study reports that vitamin E and C supplementation in 11,545 healthy male doctors (50y +) from Physicians Health Study (PHS II) had little effect on the risk of cataracts. Hopefully, this single study does not lead health care professionals and consumers to conclude that vitamin supplementation isn’t beneficial for eye health. 1. The Age-Related Eye Disease Study (AREDS) clearly demonstrated in a large-scale study that vitamin supplementation reduces the risk of progression to end-state age-related macular degeneration (AMD).
There is a tendency among people from G8 countries to think that malnutrition only happens elsewhere. This is not true. Hidden hunger and essential micronutrient inadequacies exist everywhere. Just like unemployment may be 9% nationally, there are subpopulations where over 30% can be unemployed. These disparities need to be identified and addressed. Let’s think about nutrient gaps.
An analysis of 9 individual trials with 118,765 individuals where half were given placebos and the remainder were given vitamin E supplements. The authors report that vitamin E supplementation had no effect on total stroke risk and significantly reduced the chances of a stroke to part of the brain (ischaemic) by 10%. The authors also noted that there was only a small increased chance of a hemorrhagic stroke (p < 0.045) to 8 per 10,000 people (1 to 1250 as quoted in the study). Many headlines will emphasize the finding that vitamin E increases risk of hemorrhagic stroke. Let’s give some perspective to risk vs benefits of vitamin E supplementation:
A randomized controlled trial (RCT) compared supplementing 2g docosahexaenoic acid (DHA) daily vs placebo in 402 individuals with mild to moderate Alzheimer’s disease for 18 months. The authors measured cognitive processes using Clinical Dementia Rating (CDR) and rate of brain atrophy. They concluded that DHA supplementation did not slow the progression of Alzheimer’s disease in this population and discussed whether the dose may have been too small or the results may have been affected by high omega-6 fatty acid intakes.
It was exciting to see the headline “Poor diet may worsen lung function in COPD patients” until I read the press release from the 76th American College of Chest Physicians (AACP) 76th annual meeting and learned that the authors analyzed self-reported food frequency records to estimate dietary intakes of vitamins A, C, D, E and from 13 women and 7 men. One of their conclusions was that 25% of the respondents were deficient
Within weeks, the Institute of Medicine Committee is expected to release the 2010 Dietary Reference Intakes for Vitamin D and Calcium. At that time, it will become clearer if the committee will build upon clinical practice recommendations targeting vitamin D levels of at least 30-40ng/mL for individuals at risk of osteoporosis, chronic kidney disease and other endocrine-related disorders. What might be some of the recent studies which will guide the IOM on their recommendations for vitamin D?