Dietary protein, but not carbohydrate, is a primary determinant of the onset of stroke in stroke-prone spontaneously hypertensive rats.
OBJECTIVE
Previously, an inverse association has been found between the dietary proportion of protein or fat and incidence of intracerebral hemorrhage. A positive association has been found with respect to carbohydrate intake. To examine what changes in macronutrient intake are causative, animal studies were conducted.


METHODS
Stroke-prone spontaneously hypertensive rats (SHRSP) were fed diets with varying ratios of macronutrients ad libitum, and the onset of stroke was examined.


RESULTS
When 10% of calories were from fat, rats fed a high-protein/low-carbohydrate diet (55% calories from protein) had a delayed onset of stroke, whereas rats fed a low-protein/high-carbohydrate diet (5% calories from protein) had an accelerated onset of stroke. When 30% of calories were from carbohydrate, a marked delay in the onset of stroke was observed when the diet was high in protein. When 85% of calories were from carbohydrate, rats fed 7.5% of calories as protein displayed an accelerated onset of stroke. When 20% of calories were from protein, increased fat content did not affect the onset of stroke. However, with a fat-free diet, when 20% of calories were from protein, the onset of stroke was delayed, whereas when 10% of calories were from protein, the onset of stroke was accelerated.


CONCLUSIONS
The amount of protein, but not of carbohydrate and fat, is a primary determinant of the onset of stroke. However, when calories from protein are relatively low in the diet (10%), fat is necessary to delay the onset of stroke in SHRSP.
Chiba
Tsuyoshi
T
Nutritional Science Program, National Institute of Health and Nutrition, 1-23-1 Toyama, Shinjuku-ku, Tokyo, 162-8636, Japan.
Itoh
Tatsuki
T
Tabuchi
Masaki
M
Satou
Takao
T
Ezaki
Osamu
O
D000818:Animals; D001835:Body Weight / Q000502:physiology; D004040:Dietary Carbohydrates / Q000008:administration & dosage*; D004041:Dietary Fats / Q000008:administration & dosage; D004044:Dietary Proteins / Q000008:administration & dosage* / Q000009:adverse effects*; D004435:Eating / Q000502:physiology; D006973:Hypertension / Q000150:complications* / Q000503:physiopathology; D008297:Male; D051381:Rats; D011918:Rats, Inbred SHR; D020521:Stroke / Q000209:etiology* / Q000503:physiopathology
D004040:Dietary Carbohydrates; D004041:Dietary Fats; D004044:Dietary Proteins