H. Coetzer

Calcium, gamma-linolenic acid and eicosapentaenoic acid supplementation in senile osteoporosis

Recent animal work suggests that gamma-linolenic acid (GLA) and eicosapentaenoic acid (EPA) enhance calcium absorption, reduce excretion and increase calcium deposition in bone. A pilot study was set up to test the interactions between calcium and GLA+EPA in humans. Sixty-five women (mean age 79.5), taking a background diet low in calcium, were randomly assigned to GLA+EPA or coconut oil placebo capsules; in addition, all received 600 mg/day calcium as the carbonate. Markers of bone formation/degradation and bone mineral density (BMD) were measured at baseline, 6, 12 and 18 months. Twenty-one patients were continued on treatment for a second period of 18 months, after which BMD (36 months) was measured. At 18 months, osteocalcin and deoxypyridinoline levels fell significantly in both groups, indicating a decrease in bone turnover, whereas bone specific alkaline phosphatase rose indicating beneficial effects of calcium given to all the patients. Lumbar and femoral BMD, in contrast, showed different effects in the two groups. Over the first 18 months, lumbar spine density remained the same in the treatment group, but decreased 3.2% in the placebo group. Femoral bone density increased 1.3% in the treatment group, but decreased 2.1% in the placebo group. During the second period of 18 months with all patients now on active treatment, lumbar spine density increased 3.1% in patients who remained on active treatment, and 2.3% in patients who switched from placebo to active treatment; femoral BMD in the latter group showed an increase of 4.7%. This pilot controlled study suggests that GLA and EPA have beneficial effects on bone in this group of elderly patients, and that they are safe to administer for prolonged periods of time.

Supplemented Gamma-Linolenic Acid and Eicosapentaenoic Acid Influence Bone Status in Young Male Rats: Effects on Free Urinary Collagen Crosslinks, Total Urinary Hydroxyproline, and Bone Calcium Content

The effect of different ratios of the prostaglandin precursors gamma-linolenic (GLA) and eicosapentaenoic (EPA) acids on bone status in growing rats measured as a function of free urinary pyridinium crosslinks and hydroxyproline levels was investigated. Male Sprague-Dawley rats were weaned onto an essential fatty acid deficient diet and from their fifth week, different groups of rats received a balanced, semisynthetic diet, supplemented with different ratios of GLA:EPA supplied as a mixture of evening primrose oil (EPO) and fish oil (FO). Controls were supplemented with linoleic (LA; sunflower oil) and alpha-linolenic (ALA; linseed oil) acids (3:1) or a commercially available rat chow. Animals were terminated at 84 days and femur length, ash weight, calcium content, free urinary pyridinium crosslinks (Pyd and Dpyd), total hydroxyproline (Hyp), and creatinine levels measured. Free urinary Pyd and Dpyd are good indicators of bone status and they correlated well with Hyp. Pyd and Dpyd excretion were significantly decreased in the higher GLA:EPA dietary groups and correlated well (r = 0.7) with Hyp levels. Concomitantly, bone calcium content increased significantly in the same dietary groups. These results suggest that diet supplementation with relatively high GLA:EPA ratios are more effective in inhibiting bone resorption than LA:ALA.

The effect of different n-6 n-3 essential fatty acid ratios on calcium balance and bone in rats

Prostaglandins (PGs) are known to have various effects on bone metabolism. The supplementation of essential fatty acids (EFAs), the precursors of PGs, leads to increased intestinal calcium absorption and calcium balance. It is, however, not known whether increased calcium absorption and calcium balance will enhance the calcium content in bone. Male Sprague-Dawley rats (n = 40) aged 5-12 weeks were supplemented with EFAs. The main dietary EFAs, linoleic acid (LA) and alpha-linolenic acid (ALA) were administered in a ratio of 3:1 as a control group. The conversion of LA to ALA to the PG precursors is slow, with the first step, delta-6-desaturation being rate limiting. Fatty acids beyond this rate-limiting step, gamma-linolenic acid (GLA, n-6) and eicoapentaenioc acid (EPA, n-3), were administered to different groups in the ratios 3:1, 1:1 and 1:3 to explore the impact of different ratios of n-6 and n-3 EFAs. Intestinal calcium absorption (mg/24 h) increased by 41.5% in the 3:1 supplemented group, compared with the control group. The decrease in urinary calcium (mg/24 h) correlated with the increase in n-3 level. The calcium balance (mg/24 h) and bone calcium (mg/g bone ash) increased significantly in the 3:1 (41.5% and 24.7%) group, compared with the control. The increase in bone calcium might be attributed to an EFA-induced increase in circulating PGs. An increased synthesis of PGs acting on target bone cells, as well as changes in membrane fluidity, may underlie these observations.

Biochemical profile of osteoporotic patients on essential fatty acid supplementation

Abstract Osteoporosis is the most frequent metabolic bone disorder in developed communities. No single mechanism can adequately explain the pathophysiology of osteoporosis. Recently new biochemical markers for metabolic bone disease, such as osteocalcin and procollagen have been identified and these parameters have been proven to be indicative of bone turnover. In this study, markers of bone turnover were monitored in 40 osteoporotic patients. Patients were divided into four groups to receive one of the following dietary supplements: evening primrose oil; fish oil; a mixture of evening primrose and fish oil or olive oil (placebo), for 16 weeks. Patients supplemented with fish oil showed an increase in serum calcium and an increase in urinary calcium clearance (p

Eicosapentaenoic acid and docosahexaenoic acid supplementation increases calcium balance

Sprague Dawley rats were supplemented with either fish oil, evening primrose oil or sunflower oil (control) for 12 weeks. Calcium balance and fatty acid analyses of plasma and intestinal membranes were performed at week 12. Fish oil decreased faecal calcium excretion significantly leading to an increased calcium balance (p < 0.05). Increased unsaturation of the intestinal membranes in the fish oil group may facilitate calcium absorption.

Ectopic calcification of rat aortas and kidneys is reduced with n-3 fatty acid supplementation

Supplementation with essential fatty acids has been shown to prevent the experimentally induced ectopic calcification of the kidneys known as nephrocalcinosis. Male Sprague-Dawley rats were fed a semi-synthetic diet supplemented with different essential fatty acids while being injected for a period of 10 days with calcium glubionate. After 3 weeks their kidneys and aorta were removed and the respective calcium content measured compared to the control, saline injected animals. Lipoic acid-EPA, fish oil (EPA rich) as well as the EPA monoester reduced the calcium concentration of both the kidneys and the aorta towards control values. Lipoic-EPA was the best absorbed of the three compounds and its combination of anti-oxidant together with EPA lowered the calcium content of both the aortas and the kidneys.