Coffee - September 2008

Did you know…Many beliefs abut coffee are untrue?

Recently, the Center for Science in the Public Interest published a comprehensive appraisal of scientific reports about caffeine.   The following popular beliefs are analyzed in their report findings.

Coffee is a diuretic.  False: Studies show that people who drank up to 550 milligrams (mg) of caffeine produced no more urine than when drinking caffeine-free fluids. Above 575 mg, caffeine was a diuretic.  Caffeinated drinks with less than 550 mg are hydrating and, like water, contribute to the body’s daily water needs.

Coffee increases your risk of heart attack. False:  Analysis of 10 studies of more than 400,000 people found no increase in heart disease among daily coffee drinkers.  There is little evidence that coffee and/or caffeine in typical dosages increases the risk of heart attack.  In fact, among 27,000 women followed for 15 years in the Iowa Women’s Health Study, those who drank 1-3 cups a day reduced their risk of cardiovascular disease by 24 percent, although this benefit diminished as the quantity of coffee rose.

Coffee raises your blood pressure. True, for a little while: Caffeine induces a small, temporary rise in blood pressure. But in a study of 155,000 nurses, women who drank coffee for a decade were no more likely to develop hypertension than noncoffee drinkers. A Johns Hopkins study that followed more than 1,000 men for 33 years found that coffee drinking played little overall role in the development of hypertension.

Caffeine intake causes bone loss. Slightly true:  Studies have found only a slight reduction in calcium absorption and no effect on calcium excretion.  Caffeine’s negative effect on calcium can be offset by as little as one or two tablespoons of milk. Consuming the currently recommended amount of calcium will negate caffeine’s effect on bone health.

Caffeine causes weight loss. False:  Caffeine speeds up metabolism, with 100 mg burning an extra 75-100 calories a day, but no long-term benefit to weight control has been shown. In fact, in a study of more than 58,000 men and women followed for 12 years, those who increased their caffeine consumption gained more weight than those who didn’t.

I just feel better when I drink it. True:  Consuming up to 200 mg improves sense of well-being, happiness, energy, alertness and sociability, although higher amounts sometimes cause anxiety and stomach upset.  The drug improves alertness and reaction time. In the sleep-deprived, it improves memory and the ability to perform complex tasks. In sport activity, caffeine enhances endurance and performance.

What does CPC recommend? There are health benefits to caffeine intake.  However, the most benefit seems to be obtained by limiting your intake to under about 500mg per day.  As with most things in life, moderation is key.  Many of the formerly held concerns about caffeine have been disproven through research, so go ahead, order a latte!

Diet - August 2008

Did you know…The top 3 diets all produce similar results?

A 2-year study comparing the low-fat diet, the Mediterranean diet, and the low-carbohydrate (carb) diet shows that all 3 had similar results.  Among 272 study participants who completed the study, the average weight loss ranged from 7 to 12 lbs.  All the diets improved “good cholesterol” (HDL), blood pressure and waist circumference.  But each diet had specific benefits that may help people decide which is best for them.

The low-fat diet consisted of 30% calories from fat, 1500 calorie restriction for women and 1800 calories for men.  Low-fat grains, vegetables, fruits, and legumes were encouraged, with limits on sweets and high-fat snacks.  This diet had the highest adherence rate over the 2 year period, at 90%.

The Mediterranean diet was rich in vegetables and fruit, low in red meat, substituting fish and poultry instead.  Calories were restricted as in the low-fat diet, and fat in the diet came from olive oil and nuts.  The benefits of this diet were:  favorable changes in blood glucose and insulin levels in diabetics, the greatest amount of weight loss in women (an average of 13.6 lbs.), and greatest improvement in blood pressure. C-reactive protein, a marker for heart disease, decreased significantly.

The low-carb diet limited carbs to 20 grams daily in first 2 months and gradually increased to a 120 gram limit per day.  Protein, fat and calories were not restricted.  Benefits of this diet were:  the greatest amount of weight loss in men, greatest improvement in the “good cholesterol” HDL, and the greatest decrease in triglycerides.  C-reactive protein decreased significantly in this diet also.

What does CPC recommend?
Losing extra weight improves blood pressure, cholesterol and glucose levels, which lowers risk of diabetes and heart disease.  No one diet appears to be optimal for weight loss and there are good components among each of the 3 diets in this study. If you need to lose weight, and don’t like restricting calories, the low-carb diet may be the choice for you.  If diabetes is in your family, the Mediterranean diet may be the best choice. CPC discourages diets high in saturated and trans fats and those that are so extreme they are difficult to sustain. Resources for the diets are listed below.  A balanced diet with healthful components has benefits beyond weight reduction, so here’s to healthy losing!

The research cited above is found in:  The New England Journal of Medicine, July 17, 2008, Volume 359:229-241
Information on the diets can be found in :
Low-fat diet:  American Heart Association guidelines
Mediterranean diet:  Eat, Drink and Be Healthy; The Harvard Medical School guide to healthy eating by Willett & Skerrett
Low-carb diet:  Atkins’ New diet Revolution, by RC Atkins