Titrating dietary linoleate to in vivo platelet function in man.

Platelet aggregation time significantly increased within 48 hours in response to an increase in dietary linoleate of 4% of calories while disaggregation time decreased significantly in 96 hours. A change as small as 0.5% of calories was associated with significant alterations within 4 days. In this group, dietary linoleate appears to be related to platelet function by the equations Aggregation time equals 41.14 plus 2.79 linoleate Disaggregation time equals 11.04 minus 25.52 linoleate.

Dietary calcium. A method of lowering blood pressure.

Previous work in this laboratory has shown that supplemental dietary calcium using milk as the source can lower blood pressure and serum cholesterol levels. Attempting to circumvent lactose intolerance, a 6-month crossover study of blood pressure and serum lipids in 50 free-living volunteers was done comparing 1,150 mg/day of supplemental calcium via yogurt, cottage cheese, and milk to 32 oz/day of orange juice. Systolic blood pressure responded dramatically initially to calcium supplementation and continued lower than on orange juice at 6 months, 120 +/- 1.5 to 115 +/- 1.5 mm Hg, P less than 0.2, vs. 118 +/- 1.7 to 117 +/- 1.6 mm Hg. Diastolic blood pressure and serum lipid changes were not significant. Dietary calcium supplementation may prove beneficial in lowering systolic blood pressure in the long term.

Strain differences in the hypolipemic action of dietary calcium in mature male rats.

Two strains of rats, Holtzman and Wistar, were found to differ significantly in serum and fecal lipid response when fed a corn-soya diet containing 18% added cocoa butter or corn oil and 0.08% or 1.2% calcium. Interactions of strain with fat and with calcium were noted. The Holtzman rat usually had lower serum and tissue lipid levels and higher fecal lipid levels than the Wistar rat. The magnitude of the strain differences is sufficient to explain the incompatibility of results of the different investigators who have been studying lipid metabolism.

The effect of a polyunsaturated diet upon adipose-tissue fatty acids in young coronary males. A five-year cohort study.

The fatty acid composition in the adipose tissue of 38 electrocardiographycally confirmed coronary males, mean age 43.7 years, at ideal weight on a 30%-of-calories controlled-fat diet, containing approximately 11.4% of calories as linoleic acid, was studied. The initial linoleic acid concentration in the adipose tissue was approximately 11 mole % of total fatty acids; for approximately the first 12 months it rose slightly and then rapidly increased to about 20% after 24 months. The overall response is sigmoidal in form and fits the equation: 1/y=0.025+0.066 (0.975)(x) in which y represents the adipose tissue linoleate as mole percentage of total adipose tissue fatty acids and x is the time in months.The relative increase in linoleic acid is not attributable to a decrease in any specific fatty acid.

Antioxidant effects of tocotrienols in patients with hyperlipidemia and carotid stenosis.

Antioxidants may have a role in the prevention of atherosclerosis. In the present trial, we investigated the antioxidant properties of Palm Vitee, a gamma-tocotrienol-, and alpha-tocopherol enriched fraction of palm oil, in patients with carotid atherosclerosis. Serum lipids, fatty acid peroxides, platelet aggregation and carotid artery stenosis were measured over an 18-month period in fifty patients with cerebrovascular disease. Change in stenosis was measured with duplex ultrasonography. Ultrasound scans were done at six months, twelve months, and yearly thereafter. Bilateral duplex ultrasonography revealed apparent carotid atherosclerotic regression in seven and progression in two of the 25 tocotrienol patients, while none of the control group exhibited regression and ten of 25 showed progression (P < 0.002). Serum thiobarbituric acid reactive substances, an ex vivo indicator of maximal platelet peroxidation, decreased in the treatment group from 1.08 +/- 0.70 to 0.80 +/- 0.55 microM/L (P < 0.05) after 12 mon, and in the placebo group, they increased nonsignificantly from 0.99 +/- 0.80 to 1.26 +/- 0.54 microM/L. Both tocotrienol and placebo groups displayed significantly attenuated collagen-induced platelet aggregation responses (P < 0.05) as compared with entry values. Serum total cholesterol, low density lipoprotein cholesterol, and triglyceride values remained unchanged in both groups, as did the plasma high density lipoprotein cholesterol values. These findings suggest that antioxidants, such as tocotrienols, may influence the course of carotid atherosclerosis.

Relationship between dietary fatty acid, selenium, and degenerative cardiomyopathy.

With the finding of an increasing number of cases of degenerative cardiomyopathy (DCM) amongst patients in Chongqing, Sichuan, People's Republic of China, an attempt has been made to delineate possible etiological factors. In this province endemic for Keshan disease and with considerable consumption of oils high in erucic acid, the latter does not appear to be an operative noxious agent in DCM. Additionally, it does not appear to be caused by excessive oxygen radicals, low levels of antioxidants or low selenium levels. However, lower omega-3 fatty acid levels along with higher serum lipids may be the mechanism, via higher thromboxane levels, of the production of the myocardial degeneration seen in DCM.

Reducing atherogenic risk in hyperlipemic humans with flax seed supplementation: a preliminary report.

The effect on serum lipids of a flax seed supplement consisting of three slices of flax seed-containing bread and 15 g of ground flax seed was studied in 15 hyperlipemic subjects on long-term intake (800 IU/day) of vitamin E. The flax seed, which was high in alpha-linolenic acid and fiber, and which has been reported to lower serum cholesterol in elderly subjects, was provided in a 3-month feeding trial. Serum total and low-density lipoprotein cholesterol levels were reduced significantly; high-density lipoprotein cholesterol did not change during flax seed consumption. Thrombin-stimulated platelet aggregation decreased with the supplement. Serum lipid oxidation products decreased significantly during the washout period.

Effect of stress due to anticipated minor surgery upon in vivo platelet aggregation in humans.

When measured just prior to hospital admission, platelet aggregation was faster and systolic and diastolic blood pressure were higher compared to measurements just prior to surgery and upon discharge fromthe hospital.

Dietary mustard, rape seed oils and selenium exert distinct effects on serum Se, lipids, peroxidation products and platelet aggregability.

OBJECTIVE: A degenerative cardiomyopathy (DCM) has been observed among mustard oil (MUST) users in China who eat 150 ml/week. Though the condition may be a selenium (Se) deficiency, MUST, rich in erucic acid (22:1), may bear a cardiotoxic or pro-oxidant substrate(s). The purpose of this feeding study was to compare the effects of feeding MUST, high erucic acid rape seed oil (HEAR), low erucic acid rape seed oil (LEAR) and corn oil, with or without Se addenda, on serum cholesterol, triglycerides, thiobarbituric acid reactive substances (TBARS), alpha-tocopherol, platelet aggregation and hepatic glutathione peroxidase (GSHPXase). Heart muscle pathology was evaluated. METHODS: Eighty male, weanling Wistar rats were divided into four dietary groups and fed AIN76A diet for 8 weeks with one of four oils: 1) MUST, 2) HEAR, 3) LEAR, or CORN oil. Half of each group received 0.43 mg/kg Se supplement. A purified diet was fed for 8 weeks. RESULTS: Neither Se nor oil type affected growth, though serum Se rose with dietary Se addendum (p < 0.01), and hepatic GSHPXase rose for each oil (p < 0.01). Se deprivation led to elevated serum cholesterol, except for the CORN oil group (p < 0.01). Only with LEAR did HDL cholesterol decrease. Serum triglycerides decreased with MUST and LEAR feedings (p < 0.05). In Se deficiency, HEAR led to elevated TBARS (p < 0.01), though not MUST, which contained twice as much alpha-tocopherol. Though supplementary Se protected the HEAR-fed animals from secondary peroxidation as TBARS (p < 0.01), the MUST group was not so protected. Ration Se also spared serum alpha-tocopherol for each diet group except the MUST/Se group (p < 0.05). MUST oil feeding resulted in increased platelet aggregation; MUST and HEAR resulted in increased platelet ATP release compared with CORN oil. CONCLUSION: Oxidative mechanisms may be involved in the DCM involving both Se limitation and pro-oxidant stress related to the usual intake of MUST. Human studies have been undertaken to test this thesis.

Effects of canola oil on serum lipids in humans.

Previous work in this laboratory had shown in a pilot study that canola oil could lower blood pressure and serum cholesterol levels. Attempting to extend this work to a larger cohort over a longer period, a 4-month study using a 30 ml/day addendum of canola oil as the replacement of the edible oils in the usual diet was undertaken in 36 hypercholesterolemic and/or hypertriglyceridemic subjects. Serum low-density-lipoprotein cholesterol (LDL-C) decreased from 173 +/- 9.0 to 160 +/- 10.0 mg/dl, p less than 0.025. Blood pressure, total cholesterol, and high-density-lipoprotein cholesterol (HDL-C) did not change significantly even though the HDL subfractions did, HDL2 decreasing and HDL3 increasing.

Relationship between serum lipid peroxidation products in hypercholesterolemic subjects and vitamin E status.

The relationship of serum lipid peroxidation products in hypercholesterolemic subjects to their vitamin E intake was examined in 15 such subjects with no other associated significant disease process in a 3 month trial with vitamin E supplementation. These patients with elevated serum cholesterol levels also have elevated thiobarbituric acid reactive substances (TBARS) and lipid oxidation products (LOPS). Vitamin E supplementation of 800 IU daily normalized the lipid peroxidation products but did not significantly change serum lipids.