Life Extension Magazine

Life Extension Magazine June 2007

In The News

Flavonoids Cut Cardiovascular, All-Cause Mortality in Women

Women with a high intake of certain kinds of dietary flavonoids have a reduced risk of cardiovascular mortality and premature death, scientists recently reported.* Flavonoids are plant-derived antioxidants that may benefit the heart by preventing low-density lipoprotein (LDL) oxidation, reducing inflammation, improving endothelial function, and inhibiting platelet aggregation.

Scientists evaluated the dietary intake of nearly 35,000 women who were free from cardiovascular disease at the study’s onset, and then calculated the incidence of death from cardiovascular disease, coronary heart disease, stroke, and all causes over 16 years of follow-up.

Women who consumed anthocyanidins (found in blueberries, raspberries, and red wine) experienced a lower risk of death from coronary heart disease, cardiovascular disease, and all causes. Those whose flavonone consumption (from sources such as citrus fruits) was in the top fifth of subjects had a 22% lower risk of coronary heart disease mortality compared to those who consumed the least flavonones.

—Dayna Dye

Reference

* Mink PJ, Scrafford CG, Barraj LM, et al. Flavonoid intake and cardiovascular disease mortality: a prospective study in postmenopausal women. Am J Clin Nutr. 2007 Mar;85(3):895-909.

DHA May Protect Against Breast Cancer

Consuming the omega-3 fatty acid docosahexaenoic acid (DHA) may help provide protection against breast cancer, according to a preliminary study in animals.* DHA is derived from marine sources, such as fish oil and algae.

In the laboratory, scientists examined the effects of DHA supplementation on breast tumor incidence in rats. DHA supplementation reduced the incidence of breast tumors by an impressive 30%. Further, DHA supplementation increased levels of BRCA1 protein—the product of a major tumor-suppressor gene—by 60%.

By activating a gene that confers breast cancer protection, DHA may represent an important cancer-preventive strategy. These findings support the observation that abundant dietary fish consumption may reduce the risk of breast cancer.

—Elizabeth Wagner, ND

Reference

Jourdan ML, Maheo K, Barascu A, et al. Increased BRCA1 protein in mammary tumours of rats fed marine omega-3 fatty acids. Oncol Rep. 2007 Apr;17(4):713-9.

Alternate-Day Caloric Restriction Improves Asthma-Related Symptoms

Restricting calorie intake every other day improves symptoms and decreases inflammation and oxidative stress in overweight adults with asthma, according to a recent study.*

On alternate days for two months, two men and eight women limited their caloric intake (to 380 and 320 calories, respectively). On the remaining days, they consumed as much food as they liked. Scientists monitored blood lipids, glucose, and markers of inflammation and oxidative stress periodically, and assessed airway function daily. The subjects rated their asthma symptoms and quality of life using questionnaires.

The nine participants who completed the study lost an average of 8% of their weight. Asthma symptoms, quality of life, and respiratory function significantly improved, while serum cholesterol, triglycerides, and markers of oxidative stress and inflammation decreased significantly.

The authors propose that alternate- day calorie restriction decreases free radical production while enhancing antioxidant protection. “These findings demonstrate rapid and sustained beneficial effects of alternate-day calorie restriction on the underlying disease process in subjects with asthma,” they concluded.

—Dayna Dye

Reference

* Johnson JB, Summer W, Cutler RG, et al. Alternate- day calorie restriction improves clinical findings and reduces markers of oxidative stress and inflammation in overweight adults with moderate asthma. Free Radic Biol Med. 2007 Mar 1;42(5):665-74.

Garlic Extract Limits Atherosclerosis Progression

Aged garlic extract slows the progression of atherosclerosis in adults, report scientists in California.1,2

In a randomized, double-blind, placebo-controlled pilot study, 19 patients who took aspirin and cholesterol-lowering statin drugs were followed for a year. Half received a 4-mL dose of aged garlic extract daily, while half took inactive placebo. Electron beam tomography was used to monitor changes in calcification in the subjects’ coronary arteries. Calcification underlies the transform-ation of arterial plaques to “hardened” atherosclerotic lesions, which interfere with vascular blood flow and may eventually lead to heart attack.

Compared to subjects who took placebo, those who consumed aged garlic extract had far less calcification of coronary artery plaques over the course of the study. “Garlic may prove useful for patients who are at high risk of future cardiovascular events,” the researchers concluded.2

—Dale Kiefer

Reference

1. Budoff M. Aged garlic extract retards progression of coronary artery calcification. J Nutr. 2006 Mar;136(3 Suppl):741S-4S. 2. Budoff MJ, Takasu J, Flores FR, et al. Inhibiting progression of coronary calcification using Aged Garlic Extract in patients receiving statin therapy: a preliminary study. Prev Med. 2004 Nov;39(5):985-91.

EGCG, COX-2 Inhibitor Fight Prostate Cancer

The combination of a COX-2 (cyclooxygenase-2) inhibitor drug and the green tea polyphenol EGCG (epigallocatechin gallate) works synergistically to thwart prostate cancer in cell cultures and live animals, according to a recent report.*

While scientists have known for years that anti-inflammatory COX-2 inhibitors (such as celecoxib, or Celebrex®) may help prevent cancer, concerns about the toxicity of these drugs, particularly Vioxx®, has spurred a search for complementary agents that can be combined with low doses of the drugs to help prevent cancer.

When three lines of human prostate cancer cells were treated with EGCG, a COX-2 inhibitor used in experimental studies called NS398, or a combination of the two in the laboratory, the combination resulted in greater inhibition of cancer cell growth and increased apoptosis (programmed cell death) than either agent alone. In mice implanted with human prostate cancer cells, combination treatment with EGCG and celecoxib inhibited tumor growth and reduced levels of PSA (prostate-specific antigen, a marker of prostate disease).

—Dale Kiefer

Reference

* Adhami VM, Malik A, Zaman N, et al. Combined inhibitory effects of green tea polyphenols and selective cyclooxygenase-2 inhibitors on the growth of human prostate cancer cells both in vitro and in vivo. Clin Cancer Res. 2007 Mar 1;13(5):1611-9.

Vitamin A, Carotenoids Cut Risk of Stomach Cancer

High intake of dietary vitamin A and related compounds greatly reduces the risk of developing gastric (stomach) cancer, report scientists in Sweden.* Vitamin A helps control cell proliferation and tissue differentiation throughout the body.

This prospective study evaluated the dietary intake of more than 82,000 adults for approximately seven years. Those with the highest intake of vitamin A and retinol (from dietary and supplemental sources) were much less likely to develop gastric cancer than those with the lowest intake. Higher dietary intake of the vitamin A precursors alpha-carotene and beta-carotene also reduced the risk of developing gastric cancer. Subjects with the highest intake of vitamin A and carotenoids cut their risk of gastric cancer nearly in half compared to those with the lowest intake of the vitamin.

—Dale Kiefer

Reference

* Larsson SC, Bergkvist L, Naslund I, Rutegard J, Wolk A. Vitamin A, retinol, and carotenoids and the risk of gastric cancer: a prospective cohort study. Am J Clin Nutr. 2007 Feb;85(2):497-503.

Low Testosterone May Raise Male Diabetes Risk

Men with low-normal testosterone levels are far more likely to have diabetes than men with higher levels, according to Johns Hopkins researchers.* Although low levels of hormones that promote masculine character-istics have been tied to the development of diabetes, few studies have correlated low testosterone with existing diabetes.

More than 1,400 men participating in the Third National Health and Nutrition Examination Survey were measured for levels of free, bioavailable, and total testosterone. After adjusting for age, race/ethnicity, and body fat, men in the lowest one third of free testosterone levels were four times more likely to have diabetes than men in the highest third. Men in the lowest one third of bioavailable testosterone also had a four times greater chance of existing diabetes than men in the lowest third. Low levels of free or bioavailable testosterone thus appear to be important risk factors for diabetes. These findings support the theory that male hormones directly influence sugar metabolism and the development of insulin resistance.

—Elizabeth Wagner, ND

Reference

* Selvin E, Feinleib M, Zhang L, et al. Androgens and diabetes in men: results from the Third National Health and Nutrition Examination Survey (NHANES III). Diabetes Care. 2007 Feb;30(2):234-8.

Zinc L-Carnosine Guards Against NSAID Damage

The nutritional supplement zinc L-carnosine protects the upper-gastrointestinal tract against damage often caused by the nonsteroidal anti-inflammatory drug (NSAID) indomethacin (Indocin®), according to a recent report.*

The use of NSAIDs such as ibuprofen (Advil®), naproxen (Aleve®, Naprosyn®), and piroxicam (Feldene®) is often limited by their adverse gastrointestinal effects, including stomach ulcers and upper-gastrointestinal bleeding. Sold as a prescription ulcer medication in Japan, zinc L-carnosine supports gastrointestinal healing.

In an animal model of indomethacin- and stress-induced upper-gastrointestinal damage, oral zinc L-carnosine decreased stomach injury by 75% and small intestinal injury by 50%. While adult volunteers who took indomethacin (50 mg, three times daily) for five days had increased gut permeability—a pathological change that may contribute to inflammation—no significant increase in intestinal permeability was seen when zinc L-carnosine (37.5 mg, twice daily) was co-administered. People who take NSAIDs may thus be able to guard their gastrointestinal health using supplemental zinc L-carnosine.

—Elizabeth Wagner, ND

Reference

* Mahmood A, FitzGerald AJ, Marchbank T, et al. Zinc carnosine, a health food supplement that stabilises small bowel integrity and stimulates gut repair processes. Gut. 2007 Feb;56(2):168-75.

Green Tea May Shield Against Breast Cancer

Regular consumption of green tea protects women against breast cancer, concludes a recently published case-control study from China.*

Laboratory studies have previously shown that green tea extract possesses anti-cancer effects, while epidemiological studies have suggested a link between green tea consumption and a reduced risk of breast cancer.

In a recent study, approximately 1,000 breast cancer patients were matched with an equal number of healthy control subjects. After assessing the women’s annual green tea consumption and controlling for potential confounding factors, the researchers concluded that women who consumed the most green tea were least likely to develop breast cancer. This study suggests that women may be able to lower their breast cancer risk by regularly consuming green tea.

—Dale Kiefer

Reference

* Zhang M, Holman CD, Huang JP, Xie X. Green tea and the prevention of breast cancer: a case control study in southeast China. Carcinogenesis. 2006 Dec 20; [Epub ahead of print]