In The News: June 2013

An article published online in the American Journal of Clinical Nutrition reports the finding of an association between higher urinary magnesium levels and a lower risk of ischemic heart disease.*

The study included 7,664 men and women enrolled in the Prevention of Renal and Vascular End-Stage Disease (PREVEND) study, which is a prospective investigation of albuminuria and renal and cardiovascular disease. Urinary magnesium excretion levels from samples obtained upon enrollment from 1997 to 1998 were utilized as a marker of magnesium intake. The subjects were followed for a median of 10.5 years, during which 462 ischemic heart disease events occurred.

Men and women whose urinary magnesium was among the lowest 20% of subjects had an increase in the risk of ischemic heart disease that was 60% higher than the remainder of the participants, and a risk of fatal ischemic heart disease that was 70% higher.

Editor’s Note: Authors Michel M. Joosten and his colleagues remark that reduced magnesium intake can result in cardiac arrhythmias that can cause sudden cardiac death. Additionally, magnesium helps inhibit platelet aggregation and enhances the synthesis of nitric oxide, which helps relax the blood vessels. Furthermore, increased magnesium intake has been associated with a lower risk of diabetes—a disease that significantly elevates the risk of cardiovascular disease.

The results of a trial described in the New England Journal of Medicine indicate a protective effect for a Mediterranean diet against the risk of experiencing heart attack, stroke, or death from cardiovascular causes among older adults at high cardiovascular risk.*

The study included 7,447 men and women age 55-80 with no cardiovascular disease upon enrollment who had either type II diabetes or at least three cardiovascular risk factors including smoking, hypertension, elevated LDL cholesterol levels, low HDL cholesterol levels, overweight or obesity, or a family history of premature coronary heart disease. Participants were randomized to a Mediterranean diet supplemented with extra-virgin olive oil, a Mediterranean diet supplemented with nuts, or a low-fat control diet.

The trial was concluded after a median follow-up of 4.8 years. In comparison with participants who adhered to the control diet, the average adjusted risk of experiencing a cardiovascular event was 29% lower for those who followed a Mediterranean diet plan. The findings were similar when the two Mediterranean diets were separately evaluated.

Editor’s Note: A Mediterranean diet, which is high in fruit, vegetables, fish, legumes, nuts, and olive oil, has been associated with a lower risk of cardiovascular disease and premature death in several studies of its adherents.

The Journal of the American Medical Association reported the finding of Norwegian researchers showing that supplementing with folic acid early in pregnancy helps reduce the risk of giving birth to a child with autism.*

The study included 85,176 children born between 2002 and 2008 who were followed through March 2012. Mothers were queried concerning their intake of vitamins and other supplements, particularly between 4 weeks prior to conception and week 8 of pregnancy. Over the follow-up period, 114 children were diagnosed with autistic disorder, 56 with Asperger syndrome, and 100 with pervasive developmental disorder—not otherwise specified, all of which fall under the umbrella of autism spectrum disorders.

Mothers who consumed folic acid supplements during the period from four weeks prior to conception to their eighth week of pregnancy had a 39% lower risk of giving birth to a child diagnosed with autistic disorder in comparison with mothers who did not use the supplements.

Editor’s Note: No association with Asperger syndrome or pervasive developmental disorder was noted, and no association was found for folic acid use during mid-pregnancy. “It appears that the crucial time interval is from four weeks before conception to eight weeks into pregnancy,” stated lead researcher Pål Surén, MD.

A team of researchers at Boston University Medical Center recently published results of a small clinical trial in the journal PLoS One that found that increasing blood levels of vitamin D through supplementation had far-reaching effects on the overall gene expression of white blood cells.*

The team conducted a randomized, double-blind pilot study comparing vitamin D supplementation with either 400 or 2,000 IU vitamin D3 daily for 2 months during the winter on broad gene expression in the white blood cells of healthy adults. Over half of the study participants had baseline vitamin D levels that were classified as insufficient or deficient.

Supplementation with vitamin D3 resulting in improved serum vitamin D3 concentrations was associated with at least a 1.5 fold alteration in the expression of 291 genes. In subjects with a baseline vitamin D level of less than 20 ng/mL, there was a significant difference in the expression of 66 genes versus subjects whose baseline vitamin D3 levels were over 20 ng/mL. After supplementing with vitamin D3 for 2 months, expression of these same 66 genes was similar for both groups.

Editor’s Note: The research team, led by Dr. Michael Holick, concluded that, “Our data suggest that any improvement in vitamin D status will significantly affect expression of genes that have a wide variety of biologic functions of more than 160 pathways linked to cancer, autoimmune disorders, and cardiovascular disease, which have been associated with vitamin D deficiency. This study reveals for the first time molecular finger- prints that help explain the non-skeletal health benefits of vitamin D.”

In order to investigate the protective mechanisms of an 85% pure extract of the green tea compound epigallocatechin gallate (EGCG) in the development of fibrosis, oxidative stress, and inflammation in a recently developed dietary-induced animal model of non-alcoholic fatty liver disease (NAFLD), a group of scientists from China fed female Sprague-Dawley rats either a normal rat diet or high-fat diet for 8 weeks to develop NAFLD.* For both treatments, rats were treated with or without EGCG (administered by injection, 3 times per week). At the end, blood and liver tissue samples were obtained for histology, molecular, and biochemical analyses.

Epigallocatechin gallate (EGCG) reduced the severity of liver injury in an experimental model of NAFLD associated with lower concentration of pro-fibrogenic, oxidative stress, and pro-inflammatory mediators. Therefore, they concluded that green tea polyphenols and EGCG are useful supplements in the prevention of NAFLD.

An article published in the journal Stroke reveals a protective effect for green tea and coffee against stroke in middle-aged men and women.*

Yoshiro Kokubo, MD, PhD, and associates analyzed data from 82,369 participants in the Japan Public Health Center-Based Study Cohort I and II. Questionnaires administered at enrollment provided information on green tea and coffee consumption. The subjects were followed for an average of 13 years, during which 3,425 strokes occurred.

In comparison with those whose tea drinking was categorized as seldom at less than once per month, drinking two to three cups of green tea per day was associated with a 14% lower risk of stroke and drinking at least four cups per day with a 20% reduction. Among coffee consumers, drinking the beverage three to six times per week was associated with an 11% lower risk and consuming it once per day was associated with a 20% decrease compared to seldom drinkers.

Editor’s Note: “The regular action of drinking tea and coffee largely benefits cardiovascular health because it partly keeps blood clots from forming,” Dr. Kokubo noted. Other possible mechanisms cited by the authors include the ability of compounds found in tea to protect against oxidative stress and inflammation and for those in coffee to improve blood glucose levels.

The results of a trial reported in the American Journal of Clinical Nutrition reveal a benefit for vitamin D supplementation in men and women with Parkinson’s disease.*

One hundred fourteen Parkinson’s disease patients were randomized to receive 1,200 IU vitamin D3 per day or a placebo for twelve months. Hoehn and Yahr stage, Unified Parkinson’s Disease Rating Scale, and other tests were administered to assess disease status before and after treatment. Blood samples collected at enrollment were analyzed for factors that included 25-hydroxyvitamin D and calcium levels, and variations in genes associated with vitamin D binding protein and vitamin D receptor.

By the end of the study, Parkinson’s disease stage worsened on average among those who received the placebo, but was essentially unchanged among those who received vitamin D. United Parkinson’s Disease Rating Scale scores were similarly unchanged among vitamin D-supplemented participants, but worsened in the placebo group.

Editor’s Note: A significant benefit for vitamin D3 was observed among subjects with either of two vitamin D receptor FokI genotypes, but not among those with a third FokI genotype.

Recent research conducted at the University of Surrey, England, and published by Proceedings of the National Academy of Sciences has revealed that insufficient sleep—less than six hours a night—affects the activity of over 700 of our genes.*

Insufficient sleep and circadian rhythm disruption are associated with negative health outcomes, including obesity, cardiovascular disease, and cognitive impairment, but the mechanisms involved remain largely unexplored.

In order to study this process, 26 participants were exposed to 1 week of insufficient sleep (sleep-restriction condition 5.70 hours per 24 hours) and 1 week of sufficient sleep (control condition 8.50 hours of sleep per 24 hours). Immediately following each condition, ten whole-blood RNA samples were collected from each participant, while controlling for the effects of light, activity, and food, during a period of total sleep deprivation.

The data showed that one week of insufficient sleep alters gene expression in human blood cells, reduces the amplitude of circadian rhythms in gene expression, and intensifies the effects of subsequent acute total sleep loss on gene expression.

Researchers from the Walter and Eliza Hall Institute of Medical Research have recently discovered that an immune cell population essential for intestinal health could be controlled by leafy greens in your diet.*

The immune cells, named innate lymphoid cells (ILCs), are found in the lining of the digestive system and protect the body from “bad” bacteria in the intestine. They are also believed to play an important role in controlling food allergies, inflammatory diseases, and obesity, and may even prevent the development of bowel cancers.

Dr. Gabrielle Belz, Ms. Lucie Rankin, Dr. Joanna Groom, and colleagues have discovered the gene T-bet is essential for producing a population of these critical immune cells and that the gene responds to signals in the food we eat.

Dr. Belz said that the proteins in green leafy (cruciferous) vegetables are known to interact with a cell surface receptor that switches on T-bet and might play a role in producing these critical immune cells. “Proteins in these leafy greens could be part of the same signaling pathway that is used by T-bet to produce ILCs,” Dr. Belz said. “We are very interested in looking at how the products of these vegetables are able to talk to T-bet to make ILCs, which will give us more insight into how the food we eat influences our immune system and gut bacteria.”

Olive plant leaves (Olea europaea L.) have been used for centuries in folk medicine to treat diabetes, but there are very limited data examining the effects of olive polyphenols on glucose homeostasis in humans.*

To assess the effects of supplementation with olive leaf polyphenols on insulin action and cardiovascular risk factors in middle-aged overweight men, a research team from Liggins Institute, University of Auckland, Auckland, New Zealand, set up a randomized, double-blinded, placebo-controlled, crossover trial involving 46 participants (aged 46.4±5.5 years and BMI 28.0±2.0 kg/m). The participants were randomized to receive capsules with olive leaf extract (OLE) or placebo for 12 weeks, crossing over to other treatment after a 6-week washout period.

The researchers concluded that in overweight middle-aged men at risk of developing metabolic syndrome, supplementation with olive leaf polyphenols for 12 weeks resulted in a 15% improvement in insulin sensitivity and 28% improvement in pancreatic-cell responsiveness versus placebo.

Findings from Germany’s ESTHER study reveal a lower risk of dying from cardiovascular disease, cancer, respiratory disease or any cause in men and women with higher serum levels of vitamin D.*

Reporting in the American Journal of Clinical Nutrition, Ben Schöttker and his colleagues describe the results of their study of 9,578 subjects between the ages of 50 to 74 upon enrollment in ESTHER. Vitamin D levels were measured upon enrollment and at a five-year follow-up visit. Subjects were followed for a median of 9.5 years, during which 1,083 deaths occurred.

Men and women whose vitamin D levels were classified as insufficient (between 12 and 20 ng/mL) had a 17% higher risk of dying from any cause in comparison with those whose levels were categorized as sufficient. Compared to those with sufficient levels, those with deficient levels (less than 12 ng/mL) had a 71% increased risk of dying.

Editor’s Note: Life Extension^® suggests 50–80 ng/mL as an optimal range of serum 25-hydroxyvitamin D to protect against disease.