A recently published study reveals that within 8 weeks of consuming a combination of 70% dark chocolate (50 grams per day), one serving of berries, and four servings of polyphenol rich fruits-vegetables per day, measurable improvements occur in the functioning of arteries in humans with high blood pressure. Just eight weeks and improvement was observed.
So what did the researchers do?
First, they took 102 adults with high blood pressure and instructed them to consume no chocolate, no berries and only 2 portions of fruits-vegetables per day for four weeks. After four weeks on a “low polyphenol diet” they measured forearm blood-flow response to two different vasodilators (a vasodilator increases blood flow by relaxing the muscle in the wall of arteries). Blood and urine samples were also taken.
After the four week period on a low polyphenol diet, 51 patients continued on the same diet (control group). 51 subjects had fruits and vegetables of their own choice (from a list rich in polyphenols), one serving of berries/day and 50 grams/day of 70% dark chocolate delivered free of charge to their homes weekly (intervention group).
All participants kept food diaries, answered food questionnaires, had regular consultations with nutritionists.
After 8 weeks, blood and urine testing demonstrated higher levels of polyphenols in the “high-polyphenol” group, as expected.
Most importantly the subjects consuming dark chocolate, berries and more vegetables-fruits on a daily basis demonstrated measurable and significant improvements in “endothelial function” compared to the other group. Endothelial function reveals the ability of arteries to respond to changes in demand for increased blood flow. “Endothelial” refers to the cells that line the walls of arteries, directly in contact with flowing blood. These cells are endothelial cells.
The maximum forearm blood flow response to the infusion of acetyl-choline (a vasodilator) was the test used to measure endothelial function. The maximum forearm blood flow in the high polyphenol group was TWICE that of the low polyphenol group. This large difference occurred with just eight weeks of a simple dietary intervention.
Before the dietary intervention there was no measurable difference between the two groups of subjects. After the dietary intervention there was a very large and meaningful difference.
Endothelial dysfunction is a major predictor of cardiovascular risk (heart attack and stroke). Endothelial dysfunction is BAD.
You can read about polyphenols here .
Epidemiologic studies demonstrate the health benefits of diets rich in colorful vegetables and fruits. Among the fruits berries appear to have the greatest density of important micro-nutrients on a per calorie basis.
Dark chocolate has a high content of polyphenols and multiple studies suggest significant cardiovascular benefit with just an ounce or two per day. You must be careful though about your source since the dutch method of preparation depletes the polyphenols and some brands have high amounts of cadmium or lead. The richest source of dark chocolate identified by ConsumerLab with the lowest amounts of heavy metal contaminants is 100% (bitter) Bakers Dark Chocolate. Dip it in honey or have it with sweet berries to offset the bitter taste. Avoid in the evenings or late afternoon (the caffeine content can interfere with sleep)
So eat those colorful vegetables, berries and indulge in some dark chocolate.
Here is a suggested list of vegetables, Try to get 8-9 servings per day. I give this recommendation to my patients. I adopted this from the recommendations of Doctor Terry Wahls. (From a Wheelchair to Commuting on a Bicycle: How One Woman Naturally Reversed MS | Terry Wahls MD | Defeating Progressive Multiple Sclerosis without Drugs | MS Recovery | Food As Medicine)
9 SERVINGS OF NON-STARCHY VEGETABLES PER DAY, 3 SERVINGS FROM EACH OF THREE CATEGORIES.
- DARK GREEN LEAFY VEGETABLES, 3 SERVINGS PER DAY EQUALS 3 CUPS MEASURED COOKED OR 6 CUPS MEASURED RAW
- Arugula, Beet Greens, Bok Choy, Chard all colors, Chicory, Cilantro
- Dandelion Greens, Endive, Escarole, Kale-all kinds, Parsley, Radicchio
- Radish leaves, Spinach, Turnip Greens, Watercress
- Colored vegetables, 3 cups daily:
- GREEN: Artichoke, Asparagus, Avocado (FRUIT), Cabbage (red and green) Celery, Cucumber with skin, Okra, Olives, Peppers, Zucchini with skin
- RED: Beets, red cabbage, red peppers, cooked tomatoes (fruit)
- YELLOW: Carrots, Pumpkin, Squash-summer and winter, Sweet potato,
- SULFUR RICH VEGETABLES, 3 CUPS DAILY: Some leafy greens are also sulfur rich so there is overlap in these categories
- Arugula, Asparagus, Bok Choy, Broccoli, Brussel sprouts, Cabbage, Cauliflower, Collard Greens, Garlic, Kale, Kholrabi, Leeks, Mushrooms, Onions red-yellow-white, Radishes, Scallions, Shallots, Turnip Greens, Watercress.
Eat the rainbow and enjoy good health.
You can read this study on Medscape but you must first establish a user name and password (free and open access)
Bob Hansen MD.