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Diet & Stroke Risk

What kind of diet is best for lowering my risk of stroke?

A healthy diet consisting mostly of fruits, vegetables, legumes, fish, and whole grains substantially lowers stroke risk in women. A study tracking 72,000 women for 14 years revealed that women who ate the most fruits, vegetables, fish, and whole grains were 22% less likely to have a stroke than those who ate the least. Women who ate the most “Western” diet, consisting of higher intakes of red and processed meats, refined grains, and sweets and desserts had a 58% increased risk of stroke compared with women who ate very little of these foods.1

The Nurses' Health Study followed nearly 76,000 healthy women aged 38 to 63 for 12 years to determine the relationship between whole grain intake and stroke. Higher intake of whole grain foods (about 3 servings per day) was associated with a 30% reduced risk of stroke, compared with women who ate less than a half serving per day. The beneficial effect of a diet high in whole grains was preserved even in women who had other risk factors for cardiovascular disease.2 Examples of whole grain foods include brown rice, oatmeal, and whole wheat bread and pasta; for more information on whole grain foods and daily servings see our section on Fibers & Grains.

These results are consistent with many studies that favor the so-called "Mediterranean diet" for improving vascular health and reducing stroke risk. The diet is called "Mediterranean" because it reflects the cultural dietary traditions of several countries surrounding the Mediterranean Sea, such as Greece and parts of Italy. People from these countries tend to eat large quantities of whole grains, fruits, nuts, vegetables, and fish, and fewer animal fats and proteins compared to "Westerners."

This kind of healthy diet may be even more important for stroke prevention than previously thought. The reason is that the immediate effects of certain healthy foods on your blood vessels are not usually considered in scientific studies. Much focus has been on reducing cholesterol levels through medication (statins), since they can lower total cholesterol by 50%. While diet may not lower your fasting cholesterol by that much, there is increasing evidence that a healthy Mediterranean-style diet can eliminate the negative effects a poor diet has on your blood vessels when you are not fasting. These negative effects are immediate and result from oxidative stress, the chemical burden that foods high in saturated fat and low in vitamins and antioxidants place on the cells lining your blood vessels. Considering that people eat several times a day, oxidative stress that impairs the function of your blood vessels can add up to major risk for stroke. While the diet recommended by the American Heart Association (AHA) has been proven to reduce the overall risk of cardiovascular disease and improve risk factors, the Mediterranean diet reduces stroke and heart attack by 60% in 4 years compared with the diet recommended by the AHA. A prominent study of testing the effect of cholesterol-lowering statin drugs on stroke risk found only half the risk reduction seen in the diet study!3

Another diet that can reduce the risk of stroke in women is the low-sodium Dietary Approaches to Stop Hypertension (DASH) diet, rich in fruits, vegetables, and low-fat dairy products. A 24-year study of the eating patterns of nearly 90,000 middle-aged women found that those who strictly followed the DASH diet cut their risk of stroke by 18% compared with women who didn’t follow the diet as closely.4

How does my diet affect my risk of stroke?

A healthy diet helps you avoid a stroke by preventing or controlling your stroke risk factors. For example, cutting back on saturated fat lowers blood cholesterol levels,5 eating a diet low in sodium lowers blood pressure,6 and eating more whole grains reduces your risk of developing diabetes.7 Figuring out exactly which parts of a healthy diet lower stroke risk is difficult. It may be that some of the benefit is because the more healthy foods you eat, the less room you have for unhealthy foods. People who eat a healthy diet usually have a healthier lifestyle (they exercise more and are less likely to smoke or be overweight) than people who don’t eat a healthy diet.

Can eating specific foods help prevent stroke?

There seems to be some new study every day showing that one molecule or another found in a particular food is good or bad for you. In reality, there is far more evidence recommending an overall healthy diet rather than any single food. For example, there is a lot of consistent research showing that a diet rich in fruits, vegetables and whole grains lowers your risk of stroke, but very little saying that one kind of fruit or vegetable is better than another. It is best to concentrate on maintaining a healthy diet in general, and not worrying too much about specific components. As an example of this, consider whole grains, the benefits of which are confirmed in many studies. Whether there is a single component in whole grains, like fiber or folate, that makes them healthy is difficult to determine—there appear to be benefits associated with many nutrients in whole grains and possibly their interaction with each other.8

However, there are foods that are probably worth avoiding as much as possible because of their lack of nutrients and documented health risks. These include trans fats (anything labeled “partially hydrogenated”) and saturated fats. A diet very low in these fats is associated with a reduced risk of death from cardiovascular causes (including stroke).9 Highly refined starches like sugar and white flour cause dramatic fluctuations in blood sugar, and they are associated with poor levels of triglycerides, cholesterol and C-reactive protein,10 all of which are risk factors for stroke.11-13

For much more about diet and cardiovascular disease, visit our Heart Healthy Diet section.

Should I take vitamin or antioxidant supplements to help prevent stroke?

Vitamin supplements appear to have less of a beneficial effect on vascular health than a diet that is naturally rich in vitamins and antioxidants, like a Mediterranean diet. Interestingly, studies of vitamin and antioxidant supplementation have mostly failed to show any beneficial effect on chronic disease risk, including stroke. It is thought that the mixture of nutrients found in a diet high in fruits and vegetables may be more effective than large supplemental doses of a few nutrients in isolation. For example, it has been observed that high intakes of vitamins C and E, beta-carotene, and folic acid are associated with reduced risk of heart disease and stroke, but clinical trials that have tried to reproduce these results by using large doses of single supplements have been unsuccessful. Single nutrients may not reproduce the complex interactions that vitamins and antioxidants have with each other and with other components of food. For preventing disease and stroke, it is best to get the majority of your vitamins and antioxidants directly from food.14

Do American women eat a healthy diet?

There is room for improvement in the typical American diet. From 1985 to 2000, Americans added about 300 calories to their daily diet. Specifically, the amount of grains increased 46%. Unfortunately, this was mostly refined grains (e.g., white bread); whole grains are better. Added fats increased 24% and added sugars by 23% compared with a small increase (8%) in fruits and vegetables. Meat and dairy consumption fell 1% and total dietary fat remained the same between 1985 and 1999, but rose 6% in 2000.15

According to a national health and nutrition survey, in the past 30 years women have increased their caloric intake at a rate 3 times greater than men. Between 1971 and 2000, daily caloric intake for women increased 22% from 1542 calories a day to 1877 calories. Most of the increase has been in carbohydrate consumption, going from 45% to 52% of total calories. The amount of fat consumed by women daily has also increased by 6.5 grams on average.16

For More Information

The Mediterranean Menu - A Diet You Can Enjoy
http://www.brighamandwomens.org/healtheweightforwomen/special_topics/intelihealth1203.aspx?subID=submenu10

References

  1. Fung TT, Stampfer MJ, Manson JE, Rexrode KM, Willett WC, Hu FB. Prospective study of major dietary patterns and stroke risk in women. Stroke. Sep 2004;35(9):2014-2019.
  2. Liu S, Manson JE, Stampfer MJ, et al. Whole grain consumption and risk of ischemic stroke in women: A prospective study. JAMA. Sep 27 2000;284(12):1534-1540.
  3. Spence JD. Nutrition and stroke prevention. Stroke. Sep 2006;37(9):2430-2435.
  4. Fung TT, Chiuve SE, McCullough ML, Rexrode KM, Logroscino G, Hu FB. Adherence to a DASH-Style Diet and Risk of Coronary Heart Disease and Stroke in Women. Arch Intern Med. April 14, 2008 2008;168(7):713-720.
  5. Ginsberg HN, Kris-Etherton P, Dennis B, et al. Effects of reducing dietary saturated fatty acids on plasma lipids and lipoproteins in healthy subjects: the DELTA Study, protocol 1. Arterioscler Thromb Vasc Biol. Mar 1998;18(3):441-449.
  6. Sacks FM, Svetkey LP, Vollmer WM, et al. Effects on blood pressure of reduced dietary sodium and the Dietary Approaches to Stop Hypertension (DASH) diet. DASH-Sodium Collaborative Research Group. N Engl J Med. Jan 4 2001;344(1):3-10.
  7. U.S. Department of Health and Human Services and U.S. Department of Agriculture. Dietary Guidelines for Americans, 2005. 6th Edition. Washington, DC: U.S. Government Printing Office; 2005. HHS-ODPHP-2005-01-DGA-A.
  8. Jacobs DR, Jr., Meyer KA, Kushi LH, Folsom AR. Whole-grain intake may reduce the risk of ischemic heart disease death in postmenopausal women: the Iowa Women's Health Study. Am J Clin Nutr. Aug 1998;68(2):248-257.
  9. Kromhout D. Diet and cardiovascular diseases. J Nutr Health Aging. 2001;5(3):144-149.
  10. Flight I, Clifton P. Cereal grains and legumes in the prevention of coronary heart disease and stroke: a review of the literature. Eur J Clin Nutr. Oct 2006;60(10):1145-1159.
  11. Tanne D, Koren-Morag N, Graff E, Goldbourt U. Blood lipids and first-ever ischemic stroke/transient ischemic attack in the Bezafibrate Infarction Prevention (BIP) Registry: high triglycerides constitute an independent risk factor. Circulation. Dec 11 2001;104(24):2892-2897.
  12. Salonen JT, Puska P. Relation of serum cholesterol and triglycerides to the risk of acute myocardial infarction, cerebral stroke and death in eastern Finnish male population. Int J Epidemiol. Mar 1983;12(1):26-31.
  13. Rost NS, Wolf PA, Kase CS, et al. Plasma concentration of C-reactive protein and risk of ischemic stroke and transient ischemic attack: the Framingham study. Stroke. Nov 2001;32(11):2575-2579.
  14. Woodside JV, McCall D, McGartland C, Young IS. Micronutrients: dietary intake v. supplement use. Proc Nutr Soc. Nov 2005;64(4):543-553.
  15. Wright JD, Wang CY, Kennedy-Stephenson J, Ervin RB. Dietary Intake of Ten Key Nutrients for Public Health, United States 1999-2000. Hyattsville: National Center for Health Statistics; April 17, 2003 2003. 334.
  16. Centers for Disease Control and Prevention. Trends in intake of energy and macronutrients - Unites States, 1971-2000: US Department of Health and Human Services; February 6 2004. 53 (04).

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