HYPERTENSION MANAGEMENT |
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Nutritional Consideration
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Nutritional Consideration
Nutritional factors play a large role not only in reducing the risk that hypertension will occur, but also in managing the condition after it has been diagnosed. The DASH diet study showed that diets rich in fruits and vegetables and reduced in saturated fat can both lower the risk for high blood pressure and assist with blood pressure control in hypertensive persons. The DASH study was predicted on the observation that vegetarian diets are associated with markedly reduced risk of hypertension. Vegetables and fruits accounted for approximately half of the blood-pressure-lowering effect of the diet.
Restricting sodium intake enhanced the blood-pressure-lowering effect. While the DASH diet reduced systolic blood pressure by 5 to 6 mm, in individuals eating DASH diet in combination with the lowest sodium intake (1200 mg/day) had a further pressure decrease of 5 to 8 mm Hg.
Some investigators have carried these observations a step further. Vegetarian and vegan diets reduce blood pressure in both normotensive and hypertensive individuals and have the potential to reduce or eliminate medication use in some patients. Possible mechanisms underlying these results may include a combination of the following:
Restricting sodium intake enhanced the blood-pressure-lowering effect. While the DASH diet reduced systolic blood pressure by 5 to 6 mm, in individuals eating DASH diet in combination with the lowest sodium intake (1200 mg/day) had a further pressure decrease of 5 to 8 mm Hg.
Some investigators have carried these observations a step further. Vegetarian and vegan diets reduce blood pressure in both normotensive and hypertensive individuals and have the potential to reduce or eliminate medication use in some patients. Possible mechanisms underlying these results may include a combination of the following:
WEIGHT LOSS REDUCES BLOOD PRESSURE
A meta-analysis of 105 randomized controlled trials showed that weight-reduction diets lowered blood pressure by 5.0 mm Hg systolic and 4.0 mm Hg diastolic on average. Although a reduction in plasma volume is the most likely reason, this effect may be attributed to a 15% lower activity of angiotensin-converting enzyme (ACE) after weight loss. However, weight loss is clearly not the only reason for the effect of such a diet on blood pressure, a vegetarian diets reduce blood pressure even in the absence of weight loss.
A meta-analysis of 105 randomized controlled trials showed that weight-reduction diets lowered blood pressure by 5.0 mm Hg systolic and 4.0 mm Hg diastolic on average. Although a reduction in plasma volume is the most likely reason, this effect may be attributed to a 15% lower activity of angiotensin-converting enzyme (ACE) after weight loss. However, weight loss is clearly not the only reason for the effect of such a diet on blood pressure, a vegetarian diets reduce blood pressure even in the absence of weight loss.
REDUCING OR ELIMINATING MEAT MAY INFLUENCE BLOOD VISCOSITY
Numerous studies have linked beef, veal, lamb, poultry, and animal fat to high blood pressure. Saturated fat appears to influence blood viscosity. A higher proportional intake of fatty acids from polyunsaturated sources (linoleic acid and alpha-linolenic acids), compared with saturated fats, is associated with a lower risk for developing hypertension.
Numerous studies have linked beef, veal, lamb, poultry, and animal fat to high blood pressure. Saturated fat appears to influence blood viscosity. A higher proportional intake of fatty acids from polyunsaturated sources (linoleic acid and alpha-linolenic acids), compared with saturated fats, is associated with a lower risk for developing hypertension.
VEGETABLE AND FRUITS ARE RICH IN POTASSIUM, WHICH INFLUENCES BLOOD PRESSURE
Potassium, from either food or supplements, reduces blood pressure and stroke risk. Fruits and vegetables are rich potassium sources. Some evidence also suggests that fruits and vegetables may lower blood pressure by providing antioxidant flavonoids that upregulate endothelial nitric oxide production, and by suppressing enzymes involved in the generation of superoxide radicals that are known to reduce nitric oxide availability.
Potassium, from either food or supplements, reduces blood pressure and stroke risk. Fruits and vegetables are rich potassium sources. Some evidence also suggests that fruits and vegetables may lower blood pressure by providing antioxidant flavonoids that upregulate endothelial nitric oxide production, and by suppressing enzymes involved in the generation of superoxide radicals that are known to reduce nitric oxide availability.
PLANT-BASED FOODS ARE LOW IN SODIUM
Hypertension is rare in societies whose dietary sodium intake is very low. A 2004 meta-analysis of contributors to hypertension in Finland, Italy, the Netherlands, the United kingdom, and the United States found that 9% to 17% of the risk for hypertension was attributable to dietary sodium along. In a recent meta-analysis, sodium restriction reduced systolic blood pressure by 3.6 mmHg. The principal sources of sodium are canned foods, snack foods, discretionary use of salt in food preparation or consumption, and dairy products. In their natural state, vegetables, fruits, grains, and legumes are very low in sodium.
Hypertension is rare in societies whose dietary sodium intake is very low. A 2004 meta-analysis of contributors to hypertension in Finland, Italy, the Netherlands, the United kingdom, and the United States found that 9% to 17% of the risk for hypertension was attributable to dietary sodium along. In a recent meta-analysis, sodium restriction reduced systolic blood pressure by 3.6 mmHg. The principal sources of sodium are canned foods, snack foods, discretionary use of salt in food preparation or consumption, and dairy products. In their natural state, vegetables, fruits, grains, and legumes are very low in sodium.
REPLACING ANIMAL PROTEIN WITH SOY AND OTHER PLANT PROTEINS MAY HELP LOWER BLOOD PRESSURE
Plant proteins are higher in L-arginine (an amino acid involved in production of nitric oxide) compared with animal protein, and intake of vegetable (not animal) protein is inversely related to blood pressure. A number of studies have found that soy protein supplementation reduced blood pressure significantly (5-8 mmHg systolic, 2.5-5.0 mmHg diastolic) in both normal and hypertensive individuals.
Plant proteins are higher in L-arginine (an amino acid involved in production of nitric oxide) compared with animal protein, and intake of vegetable (not animal) protein is inversely related to blood pressure. A number of studies have found that soy protein supplementation reduced blood pressure significantly (5-8 mmHg systolic, 2.5-5.0 mmHg diastolic) in both normal and hypertensive individuals.
VITAMIN C
A diet that meets the Dietary Reference Intake for vitamin C may not be adequate in persons at risk for hypertension. Studies show that blood pressure rises as vitamin C depletion occurs in humans, and higher vitamin C intakes are associated with lower blood pressure. However, there do not appear to be any additional blood pressure-lowering effects of vitamin C over an intake of 500 mg per day.
A diet that meets the Dietary Reference Intake for vitamin C may not be adequate in persons at risk for hypertension. Studies show that blood pressure rises as vitamin C depletion occurs in humans, and higher vitamin C intakes are associated with lower blood pressure. However, there do not appear to be any additional blood pressure-lowering effects of vitamin C over an intake of 500 mg per day.
VITAMIN D
The Nurses' Health Study and the Health Professionals Study reported that plasma concentrations of 25-hydroxy vitamin D were inversely associated with the risk for incident hypertension. Similarly, the National Health and Nutrition Examination Survey (NHANES) found that serum concentrations of 25-hydroxy vitamin D were inversely associated with blood pressure. Vitamin D supplementation is inversely related to plasma renin activity, and clinical as well as epidemiological evidence indicates that it may reduce blood pressure in humans. Additional evidence from clinical trials is needed to establish whether this vitamin has significant blood pressure-lowering effects.
The Nurses' Health Study and the Health Professionals Study reported that plasma concentrations of 25-hydroxy vitamin D were inversely associated with the risk for incident hypertension. Similarly, the National Health and Nutrition Examination Survey (NHANES) found that serum concentrations of 25-hydroxy vitamin D were inversely associated with blood pressure. Vitamin D supplementation is inversely related to plasma renin activity, and clinical as well as epidemiological evidence indicates that it may reduce blood pressure in humans. Additional evidence from clinical trials is needed to establish whether this vitamin has significant blood pressure-lowering effects.
MAGNESIUM
Many studies have shown that magnesium intake is inversely associated with blood pressure. The Women's Health Study of over 28,000 women found that the highest magnesium intakes (434 mg/day) were associated with a 7% lower risk for developing hypertension, compared with intakes of 256 mg/day.
Many studies have shown that magnesium intake is inversely associated with blood pressure. The Women's Health Study of over 28,000 women found that the highest magnesium intakes (434 mg/day) were associated with a 7% lower risk for developing hypertension, compared with intakes of 256 mg/day.