In The News: November 2009

In an article published in the American Heart Association journal Circulation, Harvard researchers report an association between higher plasma levels of vitamin B6 and a reduction in the risk of myocardial infarction (heart attack) in women.

The study included 144 participants in the ongoing Nurses’ Health Study who were diagnosed with myocardial infarction. The women were each matched for age, smoking status and other factors with two participants in the same study who did not have a history of heart attack at the time of the heart attack cases’ diagnoses. Stored fasting blood samples were analyzed for plasma pyridoxal 5’ phosphate (PLP), which is the predominant form of vitamin B6 that exists in circulation, and homocysteine, an amino acid which, when elevated, has been associated with an increased risk of cardiovascular disease.

Higher levels of PLP were correlated with greater dietary intake of vitamin B6, lower body mass index and lower levels of homocysteine. The researchers uncovered a significant association between plasma PLP levels and reduced heart attack risk. Women whose PLP levels were among the top one-fourth of participants at greater than 70 picomoles per milliliter had a 78% lower adjusted risk of undergoing a heart attack compared to those whose levels were lowest at less than 27.9 pmol/mL. When the women were analyzed according to age, those aged 60 and older whose PLP levels were among the top quarter were found to have a 64% lower risk than those in the lowest quarter, while those who were under 60 in the top fourth of PLP had a 95% lower risk.

The authors remark that the study’s findings are consistent with the role of vitamin B6 as a cofactor in the conversion of homocysteine to cysteine. The vitamin also plays a role in the transport of important minerals such as magnesium across cell membranes. The authors observe that the results of some research suggest that factors other than diet that control vitamin B6 levels could eventually be found to be more important in reducing heart attack risk.

The current prospective study is the first, to the authors’ knowledge, to examine the relationship of vitamin B6 levels with heart attack in postmenopausal women. “Our investigation revealed that a lower fasting concentration of PLP is significantly associated with an increased risk of myocardial infarction in predominantly postmenopausal women, a relationship that may be causal,” they write. “Future studies are needed to better understand both dietary and nondietary determinants of plasma and tissue vitamin B6 status and their role in the prevention of myocardial infarction and other chronic diseases.”

—Dayna Dye

In a recent issue of the journal Gastroenterology, researchers at the University of Texas MD Anderson Cancer Center investigated the effect of antidiabetic therapies on the risk of pancreatic cancer.*

Over a four-year period, from 2004-2008, the hospital-based case-control study involved 973 patients with pancreatic adenocarcinoma (including 259 diabetic patients) and 863 controls (including 109 diabetic patients). Personal diabetes history and other information were collected by talking to each patient personally, and the information was compared between the cases and controls. The risk of pancreatic cancer was then estimated using unconditional logistic regression analysis.

The results of the study showed that diabetic patients who had taken metformin had a 62% lower risk of pancreatic cancer compared to those who didn’t take the drug.

—Jon Finkel

An article published in the American Journal of Epidemiology reported the results of a study conducted by researchers at the Fred Hutchinson Cancer Research Center which found that vitamin C and vitamin E supplement users had a lower risk of dying over a five-year period than those who did not supplement.*

Gaia Pocobelli and colleagues evaluated data from participants in the Vitamins and Lifestyle Study. Participants who reported using vitamin C and vitamin E supplements were found to have a lower risk of dying from any cause than those who did not use the supplements. When mortality was examined by cause, multivitamin use on 6 to 7 days per week was associated with a 16% lower risk of cardiovascular disease death and vitamin E use was associated with a 28% lower risk.

—Dayna Dye

In a recent issue of the journal Biochemistry, researchers report that the dipeptide carnosine shows promise not only in preventing cataracts but also in helping to treat the condition.

Enrico Rizzarelli of the University of Catania and his colleagues tested the effects of D- and L-carnosine on bovine cultured alpha-crystallin, the major structural protein in the lens of the eye. The cultures were treated with guanidine, a compound that is known to cause cataracts via the formation of alpha-crystallin fibrils. Co-incubation of the cultures with carnosine helped inhibit fibrillation, and the addition of carnosine to pre-existing fibrils was found to almost completely dissolve them.*

In another experiment, cultured rat lenses were exposed to guanidine with or without L-carnosine. While guanidine alone caused significant lens opacification after 24 hours, pretreatment with L-carnosine prevented lens opacification by 50 to 60%. Subsequent treatment of opaque lenses with L-carnosine resulted in time-dependent recovery of transparency.

—Dayna Dye

In an article published online in Diabetes, researchers report that naringenin, a flavonoid in fruit, prevents weight gain and components of metabolic syndrome in a rodent model.*

Murray W. Huff and his associates from the University of Western Ontario used mice that exhibit disordered lipids, insulin resistance, glucose intolerance and obesity when fed a high-fat diet in their study. The animals received regular chow, a high-fat diet, or high-fat diets containing naringenin for 4 weeks.

At the end of the treatment period, mice that received naringenin had lower triglyceride and cholesterol levels than those that received the high-fat diet without naringenin. Insulin resistance was prevented and glucose metabolism was normalized. “Furthermore, the marked obesity that develops in these mice was completely prevented by naringenin,” added Dr. Huff.

“Naringenin, through its insulin-like properties, corrects many of the metabolic disturbances linked to insulin resistance and represents a promising therapeutic approach for metabolic syndrome,” he concluded.

—Dayna Dye

Higher consumption of vitamins with antioxidant effects, namely beta-carotene, vitamin C, and vitamin E, slightly reduces the risk of endometrial (uterine) cancer, according to a review of the medical literature.*

The authors identified 17 studies that pertained to diet and endometrial cancer. Data from 12 studies were pooled to determine the effects of beta-carotene, vitamin C, and vitamin E from dietary sources on endometrial cancer risk. Vitamin intakes were calculated as micrograms (μg) or milligrams (mg) per 1,000 kilocalories of diet.

All of the antioxidants reduced endometrial cancer risk. Each 1,000-μg increase in beta-carotene was associated

with a 12% reduction in risk; each 50-mg increase in vitamin C gave a 15% reduction in risk; and each 5-mg increase in vitamin E gave a 9% reduction in risk. The authors acknowledge that the reductions are modest and that one of the higher-quality studies showed no effect, so that further studies are needed.

—Laura J. Ninger, ELS

Dietary or supplemental DHA and EPA may complement antioxidant nutrients to significantly reduce the risk of developing age-related macular degeneration, according to a new study. Research conducted at Tufts University and the University of Wisconsin, and published in the British Journal of Ophthalmology, showed significant preventive benefit when DHA and EPA were added to an eye health program that also included antioxidant nutrients.1 These findings concur with earlier reports of improvements in eye health with DHA and EPA.2

Health conscious individuals obtain EPA and DHA in their fish oil supplements. Supplements previously found to protect eye health include vitamins C and E, zinc, copper, and beta-carotene.3 This recent study found that the addition of DHA was associated with a 27% reduction in the progression to advanced age-related macular degeneration, while EPA was linked to a 26% reduction when added to these nutrients.

—Christie C. Yerby, ND

A recent study in the Journal of Alzheimer’s Disease may lead to new methods when it comes to the prevention of Alzheimer’s disease. The study was done at the University of California Los Angeles (UCLA) and involved using vitamin D3 alone or with natural or synthetic curcumin to bolster the immune system and protect the brain against beta-amyloid.*

Beta-amyloid deposits cause a build-up of plaque, which is associated with an increase in brain cell damage and oxidative stress. This damage and stress can lead to cell death, which correlates to a loss of cognitive function and an increased risk of Alzheimer’s disease. In order to boost the immune system, vitamin D3 and natural or synthetic curcumin were incubated with macrophages exposed to beta-amyloid. Macrophages play an important role in boosting the immune system.

The researchers at UCLA discovered that vitamin D could help the absorption of beta-amyloid into macrophages and that curcumin compounds improved the binding of beta-amyloid to macrophages. They concluded that vitamin D3 and curcumin may help the immune system clear protein plaques linked to Alzheimer’s.

—Jon Finkel

A recent issue of JAMA published reports that contribute to the growing evidence in support of adopting healthy behaviors to protect the heart.1,2

In one article, researchers from Harvard report that men who had greater adherence to 6 factors, including maintaining a normal weight, not smoking, engaging in regular exercise, consuming alcohol in moderation, consuming breakfast cereals, and consuming fruit and vegetables, had a lower risk of developing heart failure.1

In the second article, another group from Harvard describes the benefits of positive lifestyle factors in preventing high blood pressure in women. Women who maintained a normal body weight, engaged in 30 minutes of exercise per day, consumed a low-sodium diet, consumed alcohol in moderation, used non-narcotic analgesics infrequently, and consumed supplemental folic acid had an 80% lower risk of developing hypertension, compared to the rest of the subjects.2

—Dayna Dye

New research published in the Journal of Food Science out of Tianjin University states that polysaccharides from black tea may hinder the spike in sugar levels after a meal, making it a potential weapon in the struggle to manage diabetes.*

Black tea, along with green tea and oolong tea, has been looked at to help combat a wide variety of medical ailments over the years, due to tea leaf’s polyphenol content. After studying the polysaccharide-rich fractions from the three teas, researchers found that the black tea had lower molecular weight polysaccharides. This may correlate to the dark tea’s ability to affect alpha-glucosidase activity, which lessens the spike in glucose levels in the blood following a meal.

“Many efforts have been made to search for effective glucose inhibitors from natural materials,” lead researcher Haixia Chen said in a news release. “There is a potential for exploitation of black tea polysaccharide in managing diabetes.”

—Jon Finkel

It’s common knowledge that weight problems, genetics, and disease risk are all players in a delicate balance that determines your overall health and longevity. However, The Gene Smart Diet (Rodale, 2009) takes the position that your genes, rather than being concrete elements that you need to work around to improve your vitality, can actually be influenced by what you eat.

Using the right variety and calculated portions of certain foods, Dr. Chilton devises a 5-week plan using foods designed for “lasting weight loss and optimum health.” Dotted with personal success stories from people like Mike Jones, who has lost 109 pounds on the Gene Smart diet, the book both informs and inspires. However, as interesting as much of the information that relates genes to our weight is, some of the people interviewed cite common ways that they started losing weight, namely, cutting out fatty foods like pizza, burgers, and junk food, and replacing them with fruits, vegetables, and whole grain foods. Still, the amount of weight some of the people on the Gene Diet have lost is impressive, and as far as longevity is concerned, any eating plan that makes you healthier is a good thing.

—Floyd H. Chilton, PhD

According to The End of Overeating (Rodale, 2009), America’s staggering weight problem can be boiled down to three things: excess sugar, fat, and salt in our food. If you ever had any doubt about the sheer amount of each in what you consume, you will be utterly convinced by the end of Part One of this book. And by the time you finish Part Six, you’ll look at every single item you order out as a mound of sugar, fat, and salt. Even previously thought of “safe items,” like grilled chicken, are quickly revealed to be harbingers of the unhealthy (a common method of marinating meat is through needle injection, whereby hundreds of needles pierce the meat, tearing up the connective tissue, rendering it “prechewed”).

If prechewed chicken doesn’t dissuade you, this description of how restaurants make buffalo wings just might turn you away from the popular appetizer: the fatty part of the chicken is usually par-fried at a production plant, then fried again at the restaurant, which doubles the fat. Then they’re layered with a flavoring sauce, and usually dipped in another sweet sauce by you. The result: sugar on salt on fat on fat on fat.

Overeating is filled with nuggets like this that will have you second guessing nearly every meal you eat out. Plus, you’ll be introduced to terms like hypereating (excessive eating driven by forces we find difficult to control) and priming (how one taste of food can trigger overeating). Written in a conversational tone, you’ll find Overeating to be at once eye-opening and stomach turning.

—David A. Kessler, MD

Broken down into four parts called The Body’s Six Immune Centers, Immunity Boosters, Immunity Busters, and Your Super Immunity Program, Super Immunity Foods (McGraw-Hill, 2009) is a book that compiles information about how certain foods can positively or negatively affect your health. At times, the book feels like an extended ‘Did You Know?’ column, as in: Did you know minestrone soup can help ease the pain of migraines? Or, did you know that peppermint oil can help alleviate constipation, bloating, and cramps? This style is not a bad thing, however, especially if you have migraines or bloating!

While the book offers culinary solutions to many health problems, it focuses on ways to eat to combat 13 common health conditions that weaken immunity, from arthritis to vision disorders. It also has extensive information on the top 25 immunity-boosting foods and how to incorporate them into a 4-week meal plan. With over 100 recipes to help you boost your immunity, you’ll be getting healthier one plate at a time.

—Frances Sheridan Goulart, CCN