Following on from our recent post about the most researched vitamins of 2011, we move onto the most influential articles of 2011 in vitamin research. For this exercise, we used the search engine Scopus to search for all articles containing the word “vitamin” published this year, and sorted according to the number of citations this year. Since articles published earlier in the year have an advantage in terms of the amount of time available for it to be cited, the number of citations was divided by the number of months to give a better indication of how influential the article was.
Archive for 'December 2011'
We are nearing the end of the year, and it is always a good time to look back and reflect on the previous 12 months. We monitor nutrition science every day and we have a feeling for which areas of research are booming, and which ones are less interesting. Still, all vitamins are being actively researched and the question is: which one is the most popular?
Remember, this is the holiday season. Maybe you can remember what you ate over the past few days, but are you willing to record how much? Did activities shorten your usual exercise routine? Keep your answers in mind because the two new studies in Journal of Nutrition rely upon food recall data to construct diet-nutrient-relationships. Unfortunately, in the absence of validated biomarkers, cost, and sometimes convenience, measures of diet quality and food intake are often the only data available to investigate the relationship between nutrition and health. McNaughton and colleagues used 4 day weighed food record data obtained by trained interviewers from people 65 years and older living in mainland Britain.
Muscle diseases like muscular dystrophy may reflect a failure of muscle to repair. Muscles may also be damaged when working. Vitamin E helps maintain cell membranes – muscle, immune, neuronal cells, and others. Howard and colleagues tested the hypothesis that vitamin E, acting as a membrane associated antioxidant, would promote repair of skeletal muscles in vitro. The results of these tests strongly confirm the essential role of vitamin E. According to senior co-author Dr Paul McNeil,
Warning: Read the last paragraph first. Deficiencies in B vitamins are known to elevate blood homocysteine concentrations. Supplementation with folic acid, B6 and B12 reduces homocysteine concentrations. Elevated homocysteine levels have been linked with cardiovascular disease. Therefore, B vitamin supplementation must reduce risk of death from cardiovascular disease. Paradoxically, randomized controlled trials (RCT) with B vitamin supplementation in individuals who previously have had a heart attack, eg SEARCH trial, reduced homocysteine concentrations but not primary outcomes attributable to vascular (coronary death, second heart attack, or stroke) or non-vascular (cancer) causes. In a JAMA article by Spence and Stampfer, they suggest
Within Canada and the US, the Institute of Medicine convenes a panel of experts to review the literature and set recommendations for each nutrient. These recommendations are set for the general, healthy population. That is logical. It seems appropriate. But what if you have a disease, a common disease, and your medication puts you at risk of a nutrient deficiency? A study published in Diabetes Care Journal reports that metformin, a medication prescribed for people with diabetes mellitus, may double the number of people who are vitamin B12 deficient. Unless you take a vitamin B12 dietary supplement. Use of supplements containing vitamin B12 was associated with a reduction in the prevalence of vitamin B12 deficiency.
Would you predict the number of miles your car could be driven based on the amount of money the last driver, perhaps a teenaged offspring, said they spent on buying gasoline? Not likely. It’s not the amount of gasoline purchased, it is the quantity of gas in the tank that matters. A better estimate to accurately predict the distance a car can be driven before the tank is empty is the gas gauge. So, what justifies scientists making health projections based on self-reported vitamin D supplement usage rather than serum 25(OH)D concentrations? Two recent studies compared the effect of vitamin D supplement usage vs placebo on health outcomes. Using supplement usage as a health predictor is equivalent to using gasoline receipts, rather than a vehicle’s gas gauge, to predict ‘miles-to-go’ before it runs out of gas.
Everyone knows about vitamin C and its role in supporting a healthy immune system. Nobel Laureate Linus Pauling took 3 grams of vitamin C daily to prevent colds. He encouraged people to consume vitamin C above and beyond the RDA of 75 and 90 mg daily for men and women 19y and older, respectively. Awareness of the link between citrus fruit and vitamin C became universal when sailors were nicknamed ‘limeys’ because ships were stocked with limes to prevent scurvy during long oceanic crossings. So it is shocking to read that ¾ of elderly people in Northern India and 46% in Southern India are vitamin C deficient
As a science communicator, do headlines drive you crazy? Where are readers to get perspective on individual studies? The benefits of vitamin D are getting undermined by headlines. TheHeartOrg publishes “Vitamin D fails again to affect CV mortality”. Reuters publishes “Vitamin D doesn’t prevent heart attack or cancer” with the lead sentence reading “Among seniors with a high risk of bone fractures, taking vitamin D or calcium pills has no impact on their chances of dying from cancer or vascular disease”. These headlines miss the point. Results from the RECORD trial are suspect for several reasons:
With end-of-year celebrations, it is easy to overconsume. Waistlines expand. Clothes tighten. And associated with these changes comes increased risk of non-communicable diseases – obesity, diabetes, cardiovascular disease, and others. Is there anything that we could feel good about eating? Or are the next few weeks only a time of resisting temptations? Two new studies in the American Journal of Clinical Nutrition provide hope. Research suggests that vitamin D and calcium may play a role
Vitamin B12 is a water-soluble vitamin that has several essential roles. It is needed for the formation of red blood cells, nerve sheaths and proteins. It also participates as a coenzyme in metabolic reactions, particularly recycling homocysteine to methionine. For this reason, elevated homocysteine levels, a risk factor for cardiovascular disease, can also indicate vitamin B12 deficiency. Vitamin B12 is only found in animal products putting vegetarians at risk of deficiency. Researchers are concerned that low vitamin B12 levels can place vegetarians at risk of cardiovascular disease.
More than 1.5 million American adults treat attention deficit hyperactivity disorder (ADHD) with medications. In a JAMA article published yesterday, Habel and colleagues examine the effect of these medications on risk of cardiovascular events in these young and middle-aged adults. They did not find any increased CVD risk with medication use. In an accompanying editorial, Philip Shaw MD PhD writes that “the findings support the final decision by the US FDA in 2006 not to place a black box warning of serious cardiovascular events on ADHD medications for all children and adults.” This is good news but wouldn’t it be better to remove environmental factors contributing to ADHD? The effect of azo dyes in foods and beverages on ADHD incidence is unresolved. The FDA’s Food Advisory Committee met
Acronyms are used by everyone. They are part of our culture – DSM, BMW, CEO, ATM – and we haven’t even got to nutrition. Consider healthy fats. Do you have an adequate intake of omega-3 fatty acids? Is the omega-6:omega-3 ratio of your diet healthy? Are you getting enough DHA and EPA? Interpreting this alphabet soup of acronyms may be as elusive as membership in a fraternity, say ΦβΚ. The list of acronyms is a stew of letters. A stew that may even contain the kitchen-sink. A refreshing distillation of these acronyms was written by Emily Izer, a University of Maryland dietetic intern who wrote a blog for Food Insight. She nicely explains
Is half your plate filled with fruit and vegetables? If you are an adult, are you eating 2-3 cups of vegetables and 1-2 cups of fruit daily? Probably not. And you should be. Most phytonutrients are found in fruits and vegetables. Despite dietary recommendations to increase the consumption of fruits and vegetables for decades, consumption remains low. Indeed, a single food accounts for 64% or more of the total intake of phytonutrient for 5 (α-carotene, β-cryptoxanthin, lycopene, hesperetin, and ellagic acid) of 9 phytonutrients. Antioxidant-rich diets inhibit oxidative stress and inflammation, reducing the risk of stroke.
Complementary food supplements (CFS) are a useful form of micronutrient fortification of meals. CFS is supplied as a liquid, powder or crushable tablet that is added to food directly before it is eaten to increase its nutritional content, and is also referred to as home fortification. There are many practical advantages to CFS above community- or population-level food fortification, or direct supplementation. A recent study in the European Journal of Clinical nutrition by Samadpour et al. compares three methods of CFS in a trial in a high-risk population in Iran. The authors report that around one third of children in Iran are affected by iron and zinc deficiencies. Vitamin A and D deficiencies are also common in some regions. The government provides multivitamin drops for children aged under two years. Nutritional supplementation in the 1000 days window of opportunity may have a lasting impact on long-term health and development.
Having a baby? If so, remember that folic acid is essential for neural development in infants, especially during the first trimester of pregnancy. And actually, research shows it is important during the first years of life as well. Researchers from Norway reported that folic acid supplementation in early pregnancy reduces the risk of severe language delay in children at 3 years of age.
Modern-day painter, Alev Oguz, is to have said, “The soul never ages. My soul dances without my feet. I am the music.” Unfortunately, eyes do age. According to the 2010 Gallup Study of the market for vitamins & other dietary supplements, eye health ranks in the top 5 health concerns of adults 65 years and older. In their Practice Strategies review in Optometry, Journal of the American Optometric Practice, Elliott and Sumner Williams write that 81% of adults experience eye discomfort caused by glare or fatigue while driving at night, 41% while being outside during the day, 39% while driving or riding in a car during the day, and 26% while being at the beach or boating, and 25% while working on a computer. That is most adults in typical activities.
Remember being told to eat your vegetables? Or being told to finish your milk? Or being redirected to have a piece of fruit as a snack after coming home from school? Well, new research confirms this sage advice. Rautiainen and colleagues examined food frequency questionnaires (FFQ) from women, 49-83 years, participating in the Swedish Mammography Cohort. They estimated total antioxidant capacity (TAC) of the diet using a standard database for these foods. Not surprisingly, fruits and vegetables were the best sources of antioxidants, followed by whole grains. Fruit and vegetables are great sources of antioxidants such as vitamin C and carotenoids: beta-carotene, lycopene, lutein and zeaxanthin.
Puzzles test knowledge, skill or thinking. Creativity can lead to ‘eureka’ moments but scientific advances typically require rigorous examination and effort. Scientists ‘puzzle’ by testing hypotheses – using existing evidence, without assumption of truth, and proposing explanations as a starting point for further investigation. Micronutrient deficiency is a public health puzzle for many countries. People suffer from deficiency diseases associated with vitamin D (rickets), iron (anemia), vitamin C (scurvy), vitamin A (blindness), etc. The ‘Live ad Let Die’ refers to nutrient intakes where deficiency diseases are absent but quality of life may be compromised.
Answers to nutrition-related questions are never simple. Answers tend to be like the old conundrum: which came first, the chicken or the egg? Today’s blog asks, how many self-reported food frequency questionnaires (FFQ) or dietary records are needed to accurately estimate food (and nutrient) intake over a year or decade? Is it 1? Is it 2? Is it more than 1 per year? Do correlated factors (diet, physical activity, smoking, alcohol consumption, education level, socioeconomic status) make it impossible to discern the effect of nutrients on non-communicable disease (NCD) patterns? Maybe the answer depends upon which came first. Human behavior or nutrient intake?