Green Tea & Diabetes; Breastfeeding & Adult Cholesterol Levels; Fish Oil & Senile Macular Degeneration

Health Report:

Green Tea & Diabetes

Breastfeeding & Adult Cholesterol Levels

Fish Oil & Senile Macular Degeneration

"A critical weekly review of important new research findings for health-conscious readers..."

By, Robert A. Wascher, MD, FACS

Last Updated: 8/12/2008

The information in this column is intended for informational purposes only, and does not constitute medical advice or recommendations by the author. Please consult with your physician before making any lifestyle or medication changes, or if you have any other concerns regarding your health.

GREEN TEA & DIABETES

Chronic inflammation is thought to play an important role in the development of cardiovascular diseases and many cancers. Chronic inflammation is also thought to be an important component of diabetes. Polyphenols derived from green tea are known to have significant antioxidant and anti-inflammatory properties, and intense research is underway to determine whether or not green tea supplements can favorably impact diseases that are associated, at least in part, with inflammation. A new study in the European Journal of Clinical Nutrition, from Osaka University in Japan, has evaluated green tea supplementation in patients with early adult-onset (Type 2) diabetes.

A total of 60 adult men and women with early diabetes volunteered for this prospective “crossover” study. Half of the volunteers took daily supplements of green tea powder for 2 months, while the other half of the volunteers received no supplements. During the second 2 months of the study, the two groups of study volunteers “crossed over,” and the observation group was then switched to daily green tea supplementation for 2 months, while the group that received green tea supplements during the first half of the study became the observation (or “control”) group. (Crossover studies, such as this one, provide the opportunity for researchers to compare two or more groups’ response to not only initiating therapeutic interventions, but also to assess the effects of stopping such interventions.)

In addition to monitoring blood sugar levels during the course of this clinical research study, the researchers also monitored a marker in the blood, hemoglobin A1C, that reflects the long term adequacy of diabetes control. This study also assessed the volunteers for potential changes in weight, body fat levels, blood pressure, fasting blood glucose levels, cholesterol levels (including HDL and LDL), and C-reactive protein levels (a blood marker of inflammation).

Although none of the other parameters changed significantly in the volunteers who were assigned to take green tea supplements, a significant decrease in hemoglobin A1C levels was observed in response to daily green tea supplementation.

Although this brief study cannot tell us what the long term health impact of green tea is on patients with early diabetes, it is nonetheless intriguing that daily green tea supplementation, when taken for only two months, was able to reduce hemoglobin A1C levels. The next logical step would be a prospective, randomized, double-blinded clinical study with a longer duration of follow-up.

BREASTFEEDING & ADULT CHOLESTEROL LEVELS

Many claims have been made regarding the putative lifelong benefits of breastfeeding. Now, a new review study in the American Journal of Clinical Nutrition assesses the cumulative clinical data regarding the long term effects of breastfeeding on adult cholesterol levels. In this paper, data from 17 previously published research studies, encompassing a total of 17,498 patients, was reviewed and analyzed. Altogether, 12,890 study volunteers reported being breastfed as babies, while 4,608 were primarily fed with baby formula during infancy. All of these adult volunteers had blood cholesterol levels measured as part of these 17 clinical studies. When analyzing differences in blood cholesterol levels among the 17 previously published clinical studies, the authors of this new review study adjusted their analysis to correct for differences in age, socioeconomic status, body weight and smoking status among the study volunteers.

On average, blood cholesterol levels were significantly lower among the volunteers who reported being breastfed as infants, when compared to the volunteers who were formula-fed. Among the 7 previous studies that analyzed adult cholesterol levels in volunteers who reported being either exclusively breastfed or exclusively formula-fed, the difference in blood cholesterol levels between breastfed volunteers and formula-fed volunteers was even greater and more consistent, favoring lower cholesterol levels in adults who were breastfed as babies.

FISH OIL & SENILE MACULAR DEGENERATION

Senile macular degeneration (SND) is the second most common cause of blindness in the United States, and the most common cause of blindness over the age of 65. Multiple factors associated with SMD have been identified, including advanced age, smoking, sunlight exposure (ultraviolet light), poor nutrition, stress, chronic illnesses, hereditary conditions, and some medications. Prior research has suggested that oil-rich fish might decrease the risk of developing SMD.

A new study, published in the American Journal of Clinical Nutrition, assessed the impact of eating oily fish on the incidence of SMD. In this study, volunteers 65 years of age and older underwent extensive dietary surveys to identify the frequency of oily fish consumption. These volunteers also underwent eye examinations to assess for signs of SMD.

Among the 2,275 volunteers, 105 were diagnosed with early or late SMD. Based upon dietary survey results, the authors of this study determined that eating oil-rich fish at least once per week appeared to be associated with a 50% reduction in the risk of developing SMD. Among those patients reporting the highest levels of oily fish intake, the risk of SMD was reduced by about 70%.

Disclaimer: As always, my advice to readers is to seek the advice of your physician before making any significant changes in medications, diet, or level of physical activity.

Dr. Wascher is an oncologic surgeon, professor of surgery, a widely published author, and the Director of the Division of Surgical Oncology at Newark Beth Israel Medical Center

http://www.sbhcs.com/hospitals/newark_beth_israel/mservices/oncology/surgical.html

Send your feedback to Dr. Wascher at rwascher@doctorwascher.net

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Dr. Wascher's Archives:

8-3-2008: Exercise & Weight Loss; Green Tea, Folic Acid & Breast Cancer Risk; Foreign Language Interpreters & ICU Patients

7-26-2008: Viagra & Sexual Function in Women; Patient-Reported Adverse Hospital Events; Curcumin & Pancreatic Cancer

7-13-2008: Erectile Dysfunction & Frequency of Sex; Muscle Strength & Mortality in Men; Cryoablation for Prostate Cancer

7-6-2008: Sleep, Melatonin & Breast Cancer Risk; Mediterranean Diet & Cancer Risk; New Treatment for Varicose Veins

6-29-2008: Bone Marrow Stem Cells & Liver Failure; Vitamin D & Colorectal Cancer Survival; Green Tea & Colorectal Cancer

6-22-2008: Obesity, Lifestyle & Heart Disease; Effects of Lifestyle & Nutrition on Prostate Cancer; Ginkgo Biloba, Ulcerative Colitis & Colorectal Cancer

6-15-2008: Preventable Deaths after Coronary Artery Bypass Graft (CABG) Surgery; Green Tea & Colorectal Cancer; Attention-Deficit/Hyperactivity Disorder (ADHD) & St. John’s Wort

6-8-2008: Vitamin D & Prostate Cancer Risk; Radiofrequency Ablation (RFA) of Kidney (Renal) Cancer; Antisense Telomerase & Cancer