Body composition and blood pressure: which indices of fatness show the strongest correlation?

We studied the strength of association of different indices of body composition with blood pressure (BP) in 430 healthy persons (222 males, 208 females) living in southern Saudi Arabia. The percentage of fat, fat mass (FM), fat mass index (FMI) and body mass index (BMI), but not the fat free mass (FFM) were greater in women than in men. All these indices were significantly correlated with BP except height and triceps fold thickness. However, the highest correlation with BP existed with the body weight, followed by FFM and BMI and the lowest correlation existed with FM and fat free index (FFI). Thus, this study showed that weight-related body composition indices are better correlated with BP than height-related ones. This may be of importance when addressing BP relation with the degree of fatness.

The central effects of a nitric oxide synthase inhibitor (N omega-nitro-L-arginine) on blood pressure and plasma renin.

An endothelium-derived relaxing factor has been identified as nitric oxide (NO). Peripheral and central administration of nitric oxide synthase inhibitors result in an increase in renal sympathetic nerve activity and an increase in blood pressure. The goal of our study was to determine if the increase in blood pressure following central NO synthase inhibition with N omega-nitro-L-arginine (L-NNA) is caused by the release of renin. Six groups of Sprague-Dawley rats were used. Group I (control) received intracerebroventricular (i.c.v.) artificial cerebrospinal fluid. Groups II & III received i.c.v. L-NNA, 5 & 15 micrograms/min. respectively. Group IV was treated with intravenous L-NNA, 15 micrograms/min. Group V, after bilateral nephrectomy, received i.c.v. L-NNA, 15 micrograms/min. Group VI received i.c.v. L-arginine, 60 micrograms/min. and i.c.v. L-NNA, 15 micrograms/min., simultaneously. Plasma renin concentration was measured in groups I, III, IV & V. Mean arterial blood pressure was significantly increased in groups II, III & V, i.e., following i.c.v. infusion of L-NNA. The increase in mean arterial blood pressure was significantly greater when the dose was increased from 5 to 15 micrograms/min. and it was eliminated when L-arginine was added to the infusion. The increase in blood pressure was attended by no change in heart rate. While the plasma renin concentration increased significantly in group III, this could not explain the increase in blood pressure since the nephrectomized group (V) showed no increase in renin concentration but an equivalent increase in blood pressure. The results show that acute central administration of a low dose of L-NNA increases blood pressure in rats and this increase can be prevented by central administration of L-arginine. However, intravenous infusion of the same dose (15 micrograms/min.) of L-NNA does not change blood pressure. We conclude that L-NNA acts directly within the central nervous system to increase blood pressure by a renin-independent mechanism. These results imply that central nitric oxide plays an important role in the regulation of blood pressure.

Vitamin E status in Sudanese children with protein-energy malnutrition.

Total tocopherols and alpha-tocopherols were estimated in the plasma of children with severe malnutrition (14 marasmus; 11 marasmic kwashiorkor; five kwashiorkor) and related to the total plasma lipids and different plasma lipid classes. If the mere plasma concentrations were taken as an index of the vitamin E status, five children with marasmus, five children with marasmic kwashiorkor, and two children with kwashiorkor would have been regarded as deficient (less than 500 micrograms/dl). However, if total tocopherols and alpha-tocopherols were related to the total plasma lipids, all malnourished children--except one--showed values within the limits found in healthy American children. The study shows that low tocopherol/lipid ratios are not a constant feature in severely malnourished children.

Plasma retinol and tocopherols of breast-feeding Sudanese women.

The status of vitamin A and vitamin E has been evaluated in 69 well-nourished breast-feeding Sudanese women of two villages of the irrigated Gezira area. All were consuming local Sudanese food. Plasma retinol, alpha-tocopherol, and total tocopherol were estimated by HPLC. Tocopherol values have been related to total plasma lipids, cholesterol and phospholipids. The plasma retinol concentrations ranged between 29.19-141.37 micrograms/dl (mean 63.01 micrograms/dl). All values are well above 20 micrograms/dl, the lower cut-off point of normal, and reveal a good vitamin A status. The ratio of total tocopherol/total lipids (mg/g) was with 1.35-2.72 far above the lowest normal ratio of 0.60. This means an excellent vitamin E status. Neither the retinol nor the tocopherol values showed a correlation to parity or duration of breast-feeding.

Selenium status in Sudanese children with protein-calorie malnutrition.

In 68 Sudanese children with severe protein-energy malnutrition, age 1-4 years, the selenium status was investigated and the results were compared with those of healthy Sudanese and German children. The median selenium content in plasma of healthy Sudanese children (x = 59 micrograms/L) and with those of marasmus (x = 57 micrograms/L) were found to be in the same range. It was lower than in healthy German children (x = 82 micrograms/L). Patients with marasmic kwashiorkor exhibited still lower values (x = 42 micrograms/L. Within each group of malnourished children (marasmus, marasmic kwashiorkor, kwashiorkor) there were patients with low and with "normal" selenium values (taking the values of healthy German children as normal). Hair selenium values were not different between marasmic Sudanese children and healthy German children, probably due to reduced hair growth in malnourished children. Plasma glutathione peroxidase activity was reduced concomitantly with plasma selenium in the patients with protein-calorie malnutrition. There was a good correlation between plasma selenium and plasma glutathione peroxidase activity. A follow-up study showed that plasma selenium decreased during rehabilitation in those patients who had a "normal" value before treatment. This is probably due to the low selenium content of the two dietary formulae used, which contained 18 and 25 micrograms/L Se of formula,. It remains questionable whether the low selenium states and low selenium intake exhibit a healthy risk inhibiting further rehabilitation of the patients with severe protein-calorie malnutrition.

Plasma fatty acid composition of breast-feeding Sudanese women.

The status of essential fatty acids has been evaluated in 75 well-nourished Sudanese women of two villages of the irrigated Gezira area. All were consuming local Sudanese food. The fatty acid composition of the plasma cholesterolester and phospholipid fractions was estimated by capillary gas chromatography. Compared to values published from healthy American controls (Holman et al., 1979) their values of linoleic acid, dihomo-gamma-linolenic acid, and arachidonic acid were adequate. Eicosapentaenoic acid and docosahexaenoic acid were found to be lower. Trans fatty acids were very low. With increasing levels of linoleic acid in the phospholipid fraction the arachidonic acid levels decreased, thus showing a regulation of the phospholipid arachidonic acid content. The ratio linoleic acid/dihomo-gamma-linolenic acid, reflecting the delta 6-desaturation and the following elongation step, increased with rising linoleic acid values.