Life Extension Magazine December 2005
In The News
Lowering blood sugar may reduce coronary heart disease risk in both diabetic and non-diabetic individuals, according to Johns Hopkins researchers.* The investigators found that hemoglobin A1c (HbA1c), a marker of long-term blood glucose level, is an independent predictor of heart disease risk in both diabetics and non-diabetics.
Diabetes, a condition marked by elevated blood sugar, is associated with an elevated risk of cardiovascular disease. Until now, however, it has been unclear whether elevated blood glucose independently contributes to an increased risk of heart disease.
In a prospective case-cohort study of 1,321 adults without diabetes and a cohort study of 1,626 adults with diabetes, researchers investigated the relationship between HbA1c levels and incident coronary heart disease over eight to ten years of follow up.
In participants with diabetes, each percentage-point increase in HbA1c was associated with a 14% jump in coronary heart disease risk. Although the American Diabetes Association has identified an HbA1c level of 7% as a target indicating healthy blood sugar control, these recent findings suggest that in diabetics, heart disease risk begins to increase even at HbA1c values below 7%.
The researchers found that non-diabetic individuals with HbA1c levels in the “high-normal” range of 5-6% saw an elevated risk for heart disease, even after accounting for other factors such as age, cholesterol, blood pressure, smoking, and body mass index. In fact, non-diabetic individuals with an HbA1c level of 6% or higher had almost double the heart disease risk of people with an HbA1c level below 4.6%.
Long-term elevation of blood sugar is an independent risk factor for cardiovascular disease, the investigators concluded, adding that, “For non-diabetics, lifestyle modifications, such as increased physical activity, weight loss, and eating a healthful, low-glycemic-index diet rich in fiber, fruit, and vegetables, may not only help prevent diabetes, but also reduce the risk of heart disease.”
—Elizabeth Wagner, ND
* Selvin E, Coresh J, Golden SH, Brancati FL, Folsom AR, Steffes MW. Glycemic control and coronary heart disease risk in persons with and without diabetes: the atherosclerosis risk in communities study. Arch Intern Med. 2005 Sep 12;165(16):1910-6.
A recent study in the journal Cancer, Epidemiology Bio-markers and Prevention found that people who consume vegetables and fruit in abundance have a 50% lower risk of developing pancreatic cancer than those whose vegetable and fruit intake is low.* The study is one of the largest of its kind to date.
University of California, San Francisco (UCSF) researchers analyzed the results of interviews with 532 patients with pancreatic cancer and 1,700 age- and gender-matched control subjects. Study participants were queried about diet, smoking, and other factors.
Participants who consumed five or more servings a day of a group of protective vegetables or vegetables and fruit were found to have half the risk of pancreatic cancer as those who consumed two or fewer servings daily. Consuming nine servings of vegetables and fruit a day was also associated with a 50% lower risk of pancreatic cancer compared to an intake of fewer than five servings.
Vegetables associated with the greatest amount of protection against pancreatic cancer risk included onions, garlic, beans, yellow vegetables, dark leafy vegetables, and cruciferous vegetables such as broccoli, cauliflower, and Brussels sprouts. Although eating fruit was associated with a lesser degree of risk reduction, citrus fruit offered more protection than other kinds of fruit.
According to Elizabeth A. Holly, PhD, senior study author and UCSF professor of epidemiology and biostatistics, “Pancreatic cancer is not nearly as common as breast or lung cancer, but its diagnosis and treatment are particularly difficult. Finding strong confirmation that simple life choices can provide significant protection from pancreatic cancer may be one of the most practical ways to reduce the incidence of this dreadful disease.”
* Chan JM, Wang F, Holly EA. Vegetable and fruit intake and pancreatic cancer in a population-based case-control study in the San Francisco bay area. Cancer Epidemiol Biomarkers Prev. 2005 Sept;14:2093-7.
The omega-3 fatty acid docosahexaenoic acid (DHA) reduces levels of a protein known to cause damaging plaques in the brains of Alzheimer’s patients, and a derivative of DHA helps protect brain cells against cell death, report scientists at Louisiana State University.*
While previous research has suggested that DHA reduces the risk of cognitive decline, its mechanism of action has been unknown.
Collaborating investigators at LSU and at Brigham and Women’s Hospital in Boston discovered that DHA, which is found in coldwater fish such as mackerel, sardines, and salmon, reduces the secretion of the protein amyloid beta, or Abeta, in human neural cells. Amyloid beta plaques accumulate in the brains of those with Alzheimer’s disease. Furthermore, DHA spurred the production of neuroprotectin D1, which has neuroprotective effects on gene expression, promoting the survival of brain cells.
In examining postmortem human brain samples of people with Alzheimer’s disease, the researchers found that an area of the brain critical to memory formation and cognition had greatly diminished levels of neuroprotectin D1. Dr. Greg M. Cole, associate director of the Alzheimer’s Disease Research Center at UCLA’s School of Medicine, noted that both DHA and its derivative, neuroprotectin D1, “are effective in treating human brain cells and reducing the inflammation and toxicity from a toxin called beta amyloid that is widely believed to cause Alzheimer’s.”
Fish oils may thus represent a crucial component of a nutritional strategy to help prevent cognitive decline and Alzheimer’s disease.
—Elizabeth Wagner, ND
* Lukiw WJ, Cui JG, Marcheselli VL, et al. A role for docosahexaenoic acid-derived neuroprotectin D1 in neural cell survival and Alzheimer disease. J Clin Invest. 2005 Sept 8; [Epub ahead of print]
Curcumin helps lower elevated cholesterol levels induced by a high-fat diet in rats, according to investigators at Al-Azhar University in Cairo, Egypt.* By promoting a healthy blood lipid profile, curcumin may thus help reduce the risk of cardiovascular disease.
The researchers studied three groups of 10 rats per group. The control group was fed standard rat chow. One experimental group received a high-cholesterol diet enriched with 0.5% curcumin by weight, while the other experimental group received a high-cholesterol diet without curcumin. Cholesterol profiles, liver enzyme levels, and markers of antioxidant activity in the three groups of rats were examined after one week on the high-cholesterol diet.
The high-cholesterol diet increased total cholesterol levels dramatically, but adding curcumin reduced total cholesterol by 21% compared to the high-cholesterol group that did not receive curcumin. In the curcumin-supplemented rats, triglyceride levels dropped by 25-31%, while low-density lipoprotein (LDL) levels fell by 58% compared to the unsupplemented group. The curcumin-fed animals also demonstrated a 51% increase in high-density lipoprotein (HDL) levels. Moreover, curcumin significantly reduced the ill effects of a high-cholesterol diet on markers of liver health in the rats, though it had no discernible effect on blood markers of oxidation.
Curcumin thus appears to improve several blood lipid parameters by lowering total cholesterol, LDL, and triglycerides, while raising HDL levels. The researchers believe that curcumin exerts its cholesterol-lowering actions by modulating cholesterol absorption, degradation, or elimination, rather than through an antioxidant mechanism. Long used as an anti-inflammatory agent, curcumin may also help protect cardiovascular health through its beneficial effects on blood lipids.
—Linda M. Smith, RN
* Arafa HM. Curcumin attenuates diet-induced hypercholesterolemia in rats. Med Sci Monit. 2005 Jul;11(7):BR228-34.