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Biomedical subjects

G J Nelson

Publications and source records attributed to G J Nelson.

At least 37 records · Page 2Linked to original sources
PubMed1997

The effect of dietary docosahexaenoic acid on platelet function, platelet fatty acid composition, and blood coagulation in humans.

The effect of dietary docosahexaenoic acid (DHA) in the absence of eicosapentaenoic acid (EPA) has been studied infrequently in humans under controlled conditions. This 120-d study followed healthy, adult male volunteers who lived in the metabolic research unit (MRU) of the Western Human Nutrition Research Center for the entire study. The basal (low-DHA) diet consisted of natural foods (30 en% fat, 15 en% protein, and 55 en% carbohydrate), containing < 50 mg/d of DHA, and met the recommended daily intake for all essential nutrients. The high-DHA (intervention) diet was similar except that 6 g/d of DHA in the form of a triglyceride containing 40% DHA replaced an equal amount of safflower oil in the basal diet. The subjects (ages 20 to 39) were within -10 to +20% of ideal body weight, nonsmoking, and not allowed alcohol in the MRU. Their exercise level was constant, and their body weights were maintained within 2% of entry level. They were initially fed the low-DHA diet for 30 d. On day 31, six subjects (intervention, group A) were placed on the high-DHA diet; the other four subjects (controls, group B) remained on the low-DHA diet. Platelet aggregation in platelet-rich plasma was determined using ADP, collagen, and arachidonic acid. No statistical differences could be detected between the amount of agonist required to produce 50% aggregation of platelet-rich plasma before and after the subjects consumed the high-DHA diet. The prothrombin time, activated partial thromboplastin time, and the antithrombin-III levels in the subjects were determined, and, again, there were no statistically significant differences in these three parameters when their values were compared before and after the subjects consumed the high-DHA diet. In addition, the in vivo bleeding times did not show any significant difference before and after the subjects consumed the high-DHA diet (9.4 +/- 3.1 min before and 8.0 +/- 3.4 min after). Platelets from the volunteers exhibited more than a threefold increase in their DHA content from 1.54 +/- 0.16 to 5.48 +/- 1.21 (wt%) during the DHA feeding period. The EPA content of the subjects' platelets increased from 0.34 +/- 0.12 to 2.67 +/- 0.91 (wt%) during the high-DHA diet despite the absence of EPA in the subjects' diets. The results from this study on blood clotting parameters and in vitro platelet aggregation suggest that adding 6 g/d of dietary DHA for 90 d to a typical Western diet containing less than 50 mg/d of DHA produces no observable physiological changes in blood coagulation, platelet function, or thrombotic tendencies in healthy, adult males.

Adenosine Diphosphate↗
PubMed1997

The effect of dietary docosahexaenoic acid on plasma lipoproteins and tissue fatty acid composition in humans.

Normal, healthy male volunteers (n = 6) were fed diets [high docosahexaenoic acid-DHA] containing 6 g/d of DHA for 90 d. The stabilization (low-DHA) diet contained less than 50 mg/d of DHA. A control group (n = 4) remained on the low-DHA diet for the duration of the study (120 d). Blood samples were drawn on study days 30 (end of the stabilization period), 75 (midpoint of the intervention period), and 120 (end of the intervention period). Adipose tissue (AT) samples were taken on days 30 and 120. The plasma cholesterol (C), low density lipoprotein (LDL)-C and apolipoproteins (apo) [Al, B, and lipoprotein (a)] were unchanged after 90 d, but the triglycerides (TAG) were reduced from a mean value of 76.67 +/- 24.32 to 63.83 +/- 16.99 mg/dL (n = 6, P < 0.007 using a paired t-test) and the high density lipoprotein (HDL)-C increased from 34.83 +/- 4.38 mg/dL to 37.83 +/- 3.32 mg/dL (n = 6, P < 0.017 using a paired t-test). The control group showed no significant reduction in plasma TAG levels. Apo-E, however, showed a marked increase in the volunteers' plasma after 90 d on the high-DHA diet, from 7.06 +/- 4.47 mg/dL on study day 30 to 12.01 +/- 4.96 mg/dL on study day 120 (P < 0.002 using a paired t-test). The control subjects showed no significant change in the apo-E in their plasma (8.46 +/- 2.90 on day 30 vs. 8.59 +/- 2.97 on day 120). The weight percentage of plasma DHA rose from 1.83 +/- 0.22 to 8.12 +/- 0.76 after 90 d on the high-DHA diet. Although these volunteers were eating a diet free of eicosapentaenoic acid (EPA), plasma EPA levels rose from 0.38 +/- 0.05 to 3.39 +/- 0.52 (wt%) after consuming the high-DHA diet. The fatty acid composition of plasma lipid fractions--cholesterol esters, TAG, and phospholipid--showed marked similarity in the enrichment of DHA, about 10%, after the subjects consumed the high-DHA diet. The DHA content of these plasma lipid fractions varied from less than 1% (TAG) to 3.5% (phospholipids) at baseline, study day 30. EPA also increased in all plasma lipid fractions after the subjects consumed the high-DHA diet. There were no changes in the plasma DHA or EPA levels in the control group. Consumption of DHA also caused an increase in AT levels of DHA, from 0.10 +/- 0.02 to 0.31 +/- 0.07 (wt%) (n = 6, P < 0.001 using a paired t-test), but the amount of EPA in their AT did not change. Thus, dietary DHA will lower plasma TAG without EPA, and DHA is retroconverted to EPA in significant amounts. Dietary DHA appears to enhance apo-E synthesis in the liver. It appears that DHA can be a safe and perhaps beneficial supplement to human diets.

Adipose Tissue↗
PubMed1995

Low-fat diets do not lower plasma cholesterol levels in healthy men compared to high-fat diets with similar fatty acid composition at constant caloric intake.

In most studies reporting the effects of high-fat (HF) and low-fat (LF) diets on human plasma fatty acids (FA) and lipoprotein levels, the design involved adding to the diet an oil that had an FA composition (FAC) very different from the FAC of the control diet. Thus, it is difficult to determine if simply reducing the fat content of the diet without changing the dietary FAC changes the tissue FAC or alters plasma lipid levels. In this study, we fed diets that contained either 22 or 39% of calories from fat, but had no differences in their FAC, for 50 d to a group (n = 11) of healthy men (20-35 y). Thus, the polyunsaturated/saturated ratios (1.0) of the diets were identical as were the n-3/n-6 ratio and the monounsaturated-to-total fat ratios. The diets contained (wt% of total fat) approximately 28% saturated FA, 33% monounsaturated cis-FA, 6% monounsaturated trans-FA, 22% n-6 polyunsaturated FA, and 7% n-3 polyunsaturated FA, and 4% other minor FA. The diets consisted of natural foods and were formulated to contain 16 en% protein, either 45 or 62 en% carbohydrate (CHO) and at least the recommended daily allowance for all micronutrients. Both diets contained 360 mg of cholesterol per day. All subjects were given the HF diet for 20 d, and then six were placed on the LF and the other five remained on the HF diet for 50 d. The two groups were crossed-over for the remaining 50 d of the study. The subjects' baseline total cholesterol level was 173 mg/dl, after 50 d on the HF diet it was 177 mg/dl and after 50 d on the LF diet, 173 mg/dl. The differences were not significant, and there were no significant changes in either the LDL or HDL cholesterol levels with either diet. Triglyceride levels, and consequently very low density lipoprotein levels, rose significantly on the LF, higher CHO diet compared to the levels found in the subjects on the HF diet (91.5 and 66.4 mg/dl respectively, P < 0.002). The linoleic acid content of the plasma, platelets, and red blood cells was significantly (P < 0.05) reduced in the LF diet compared to HF diet, without any obvious physiological effects. Hence, many earlier observations indicating reductions in plasma lipid levels when people are on LF diets may be due to changes in the FAC of the diet, not the reduction in fat calories.

Adult↗
PubMed1994

Decreased systemic thromboxane A2 biosynthesis in normal human subjects fed a salmon-rich diet.

Nine normal male subjects were fed a reference diet typical of that consumed in the United States and a diet containing approximately 450 g salmon (salmon-rich diet). The salmon diet contained approximately 6 g omega 3 fatty acids that comprised 2.0% energy intake/d for each individual. The percent energy contribution of protein, carbohydrate, and fat (19%, 56%, and 25%, respectively) was identical for the two diets. Urinary excretion of 2,3-dinor-thromboxane B2 was significantly lower (0.74 +/- 0.26 ng/24 h) with the salmon diet compared with the reference diet (0.95 +/- 0.31 ng/24 h). In addition, in vitro generation of thromboxane B2 in response to collagen-stimulated aggregation of platelet-rich plasma from subjects consuming the salmon diet was reduced (1.87 +/- 0.79 ng/mL) compared with subjects consuming the reference diet (3.10 +/- 1.81 ng/mL). Urinary 2,3-dinor-6-oxo-prostaglandin F1 alpha excretion in subjects was not significantly different between the salmon diet (0.69 +/- 0.33 ng/24 h) and the reference diet (0.81 +/- 0.44 ng/24 h).

Adult↗
PubMed1993

The urinary excretion of thiobarbituric acid reactive substances and malondialdehyde by normal adult males after consuming a diet containing salmon.

In this study we investigated the output of thiobarbituric acid reactive substances (TBARS) and malondialdehyde (MDA), as thiobarbituric acid (TBA)-MDA adduct, in the urine from subjects eating a diet in which the only source of n-3 long-chain, polyunsaturated fatty acids was fresh salmon. Nine healthy men, ages 30-65, were confined in the United States Department of Agriculture Western Human Nutrition Research Center, San Francisco, CA, for 100 d; food intake and exercise levels were controlled. All subjects were placed on a stabilization diet (StD) for 20 d, then six were fed the salmon diet for 40 d. The others remained on the StD. The groups switched diets for the last 40 d. Both diets were isocaloric (16% protein, 54% CHO and 30% fat by energy %). The salmon diet contained 7.5% of calories from n-6 fatty acids (FAs) and 2% from n-3 FAs, primarily eicosapentaenoic acid and docosahexaenoic acid in a 50:60 ratio, while the StD contained 7.5% from n-6 FAs and < 0.3% n-3 FAs (with presumably no significant amounts of C20 or C22 n-3 FAs). Twenty-four hour urinary output was collected, and 2% 3-d pool samples prepared for analysis of urinary TBARS and the TBA-MDA adduct. The total urinary output of each individual varied considerably, and on a daily basis the concentration of autoxidation products in an individual's urine varied also.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Dietary alpha-linolenic acid alters tissue fatty acid composition, but not blood lipids, lipoproteins or coagulation status in humans.

We examined the effect of dietary alpha-linolenic acid (ALA) on the indices of lipid and coagulation status and on the fatty acid composition of serum and peripheral blood mononuclear cell (PBMNC) lipids in ten healthy men (age 21-37 yr) who consumed all their meals at the Western Human Nutrition Research Center for 126 d. There was a stabilization period of 14 d at the start when all 10 subjects consumed the basal diet (BD) containing 23.4 energy percent (en%) fat and two intervention periods of 56 d each. During the first intervention period, 5 subjects consumed the BD containing 23.4 en% fat, and 5 subjects consumed a diet providing 6.3% calories from alpha-linolenic acid [flaxseed oil (FSO) diet containing 28.8 en% fat]. Diets were crossed over between the two groups during the second intervention period. Feeding the FSO diet did not significantly alter serum triglycerides, cholesterol, high-density lipoproteins, low-density lipoproteins, apoprotein A-I and apoprotein B when compared to the corresponding values in the subjects fed the BD, nor was there any effect of the FSO diet on the bleeding time, prothrombin time and partial prothrombin time for these subjects. Feeding the ALA-containing diet did cause a significant increase in ALA concentration in serum (P < 0.001) and PBMNC lipids (P < 0.05). It also caused a significant increase (P < 0.05) in the eicosapentaenoic and docosapentaenoic acid contents of PBMNC lipids, and a decrease (P < 0.01) in linoleic and eicosatrienoic acid contents of serum lipids.(ABSTRACT TRUNCATED AT 250 WORDS)

8,11,14-Eicosatrienoic Acid↗
PubMed1992

Salmon diet and human immune status.

We examined the effect of feeding a salmon-containing diet on the immune status of nine healthy men (age 30-65 years) who lived at the metabolic suite of the Western Human Nutrition Research Center for 100 days. During the first 20 days all nine subjects consumed a basal diet (BD). For the next 40 days, three subjects continued to consume BD, while the diet of remainder six subjects was modified to contain 500 g salmon every day. During the last 40 days, the diets of the two groups were crossed over. Feeding 500 g salmon daily for 40 days did not significantly suppress the blastogenesis of peripheral blood mononuclear cells cultured with phytohemagglutinin, Concanavalin A, protein A or pokeweed when compared to the corresponding pre-salmon diet values. It also did not significantly affect the delayed hypersensitivity skin response to seven recall antigens, serum concentrations of immunoglobulins G, M, and A, and complement fractions C3 and C4. Our results indicate that the short-term consumption of a high fish (salmon)-containing diet does not adversely affect the immune system, as has been reported with fish oil supplements.

Adult↗
PubMed1991

The effect of a salmon diet on blood clotting, platelet aggregation and fatty acids in normal adult men.

This study was designed to measure the effect of dietary n-3 fatty acids (FA) on platelets and blood lipids. Healthy men (n = 9), ages 31 to 65, were fed diets in which salmon was the source of n-3 fatty acids. They were confined in a nutrition suite at this Center for 100 days. Food intake and exercise levels were rigidly controlled. Initially they were placed on a stabilization diet for 20 days, then six men were fed the salmon diet for 40 days. The others remained on the stabilization diet. The two groups switched diets for the last 40 days of the study. Both diets were isocaloric [16% protein, 54% carbohydrate, and 30% fat by energy-% (En%)]. The salmon diet contained 7.5% of calories from n-6 FA and 2% from n-3 FA, primarily eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in a 40:60 ratio, while the stabilization diet contained 7.5% of calories from n-6 FA and less than 0.3% n-3 FA, mainly 18:3n-3. The bleeding time was unaffected by the diets in this study. The prothrombin time was shortened (11.6 sec. vs. 12.6 sec., p less than 0.01) for the subjects consuming the salmon diet as compared to that measured after 20 days of the stabilization diet. Mean platelet volume increased significantly during the period in which the volunteers consumed the salmon diet compared to the baseline diet (p less than 0.01), while the mean platelet levels decreased. Platelet aggregation (PA) was measured in platelet rich plasma before, during, and after the salmon diet using collagen, ADP, arachidonic acid (AA), and thrombin agonists. The PA threshold for ADP was significantly increased for the subjects on the salmon diet (p less than 0.05). No change in the PA threshold was detected for collagen or thrombin. The PA threshold for AA was unchanged also, but the platelets in subjects consuming the salmon diet had a prolonged time to maximum aggregation (p less than 0.01) with this reagent compared to platelets from men on the stabilization diet. Plasma, red cell, and platelet total FA composition was determined by capillary GLC. While the men consumed the salmon diets, there were marked increases (3 to 10-fold) in the EPA and DHA levels in all blood components with concomitant decreases in linoleic acid and AA levels.(ABSTRACT TRUNCATED AT 400 WORDS)

Adenosine Diphosphate↗
PubMed1991

Effect of a salmon diet on the distribution of plasma lipoproteins and apolipoproteins in normolipidemic adult men.

The effects of n-3 fatty acids on plasma lipids, lipoproteins and apoproteins have usually been studied in humans after feeding of purified fish oil. This study describes the effect of a natural diet, containing salmon as the source of n-3 fatty acids, on these parameters as compared to a diet very low in n-3 fatty acids. The subjects were nine normolipidemic, healthy males who were confined to a nutrition suite for 100 days. During the first 20 days of the study the participants were given a stabilization diet consisting of 55% carbohydrates, 15% protein, and 30% fat. The n-3 content of this diet was less than 1%, and it contained no 20- or 22-carbon n-3 fatty acids. After the stabilization period the men were split into two groups, one group continued on the stabilization diet while the other received the salmon diet that contained approximately 2.1 energy percent (En%) of calories from 20- and 22-carbon n-3 fatty acids. Both diets contained equal amounts of n-6 fatty acids. This regime continued for 40 days, then the two groups switched diets for the remainder of the study. Plasma triglycerides were lowered significantly (p less than 0.01) and high density lipoprotein cholesterol (HDL-C) was significantly elevated (p less than 0.01) after the men consumed the salmon diet for 40 days. The very low density lipoproteins (VLDL) were lowered, but the trend did not reach statistical significance during the intervention period.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Absorption and transport of fat in mammals with emphasis on n-3 polyunsaturated fatty acids.

The current state of knowledge concerning the absorption and transport of dietary fat with emphasis on long-chain polyunsaturated n-3 fatty acids in mammals is reviewed. It is apparent that long-chain polyunsaturated n-3 fatty acids, either as free acids or as part of triglycerides, are readily absorbed in the gut and transported by the circulatory system. Indeed, it would appear that long-chain polyunsaturated n-3 fatty acids are digested, absorbed and transported similarly to other long-chain fatty acids with only minor variations, although there is much that is still not understood about these processes. The main unresolved issues in the area of the absorption and transport of long-chain polyunsaturated n-3 fatty acids appear to be: 1) If they, when located in the 2-position of triglycerides, have unique metabolic pathways; and 2) whether the unnatural forms, i.e., methyl or ethyl ester derivatives, are suitable vehicles for administration as dietary supplements. The effect in man of dietary, long-chain polyunsaturated n-3 fatty acids on blood serum lipid and lipoprotein levels, particularly the low density lipoproteins, remains controversial, except for the well-documented reduction in serum triglyceride levels. Also, there is uncertainty regarding their distribution and metabolism in tissues. Finally, if the consumption of long-chain polyunsaturated n-3 fatty acids has beneficial health consequences, what is the appropriate therapeutic dose? In view of these important, unresolved issues and uncertainties, it would seem prudent to direct additional research toward a better understanding of the overall process by which fat is digested, absorbed and transported.

Animals↗
PubMed1988

Effects of type of dietary fat on indices of immune status of rabbits.

We have compared the effects of dietary saturated and unsaturated fats of the n-6 and n-3 types on the immune status of male New Zealand white rabbits. Four groups of rabbits (n = 8) were fed purified diets containing one of the following fats (7.6% w/w, 23 kcal%) for 5 mo, hydrogenated soybean oil (HSO); safflower oil (SFO); linseed oil (LSO); or menhaden oil (MHO). In vitro proliferation of peripheral blood lymphocytes (PBL) cultured with T-cell mitogens was significantly higher in the LSO group than in the other three groups, and that in the HSO group was higher than in the MHO and SFO groups which were not different from each other. Proliferation of PBL in response to B-cell mitogens was significantly higher in the LSO group than in the SFO and MHO groups. In vitro proliferation of splenocytes (SPC) from the LSO group was higher than that from the other three groups only when SPC were cultured with T-cell mitogens. Serum antibody levels against bovine serum albumin were significantly higher in the LSO group than in the SFO group after second and third immunizations. Spleen weights, number of SPC or PBL, and delayed-type hypersensitivity were not different among the four dietary groups. Our data show that linseed oil diet enhanced several indices of immune status in rabbits.

Animals↗
PubMed1987

The influence of dietary fat on the lipogenic activity and fatty acid composition of rat white adipose tissue.

The in vivo fatty acid synthesis rate, selected enzyme activities and fatty acid composition of rat white adipose tissue from animals fed semisynthetic diets of differing fat type and content were studied. All animals were starved for 48 hr and then refed a fat-free (FF) diet for 48 hr. They were then divided into three groups. One group was continued on the FF diet for 48 hr. Another group was fed a diet containing 44% of calories from corn oil (CO). The final group was fed a diet containing 44% of calories from completely hydrogenated soybean oil (HSO). The animals on the FF diet had a marked increase in adipose tissue fatty acid synthesis during the 96-hr feeding period (as measured by 3H incorporation into adipose fatty acids). Addition of either CO or HSO to the diets did not significantly inhibit fatty acid synthesis in dorsal or epididymal adipose tissue. The activities of the enzymes' fatty acid synthetase, ATP-citrate lyase and glucose-6-phosphate dehydrogenase increased on the FF diet and generally were not inhibited significantly by the addition of either fat to the diets. Linoleic acid was the major polyunsaturated fatty acid (ca. 22%) in adipose tissue. Monounsaturated fatty acids (palmitoleic, oleic, cis-vaccenic) made up ca. 38% of the total adipose fatty acids, while saturated fatty acids accounted for about 32% (myristic, palmitic and stearic). White adipose tissue in mature male rats was a major depot for n-3 fatty acids.(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue↗
PubMed1987

The effects of fat-free, saturated and polyunsaturated fat diets on rat liver and plasma lipids.

The liver and plasma lipids and fatty acid composition of rats fed synthetic diets of differing fat type and content were studied. All animals were starved for 48 hr and then refed a high carbohydrate, fat-free diet for 48 hr. They were then divided into three groups and fed for an additional 48 hrs the following: group 1, the fat-free diet; group 2, a diet containing 44% of calories from corn oil; and group 3, a diet containing 44% calories from completely hydrogenated soybean oil. The total lipid concentration of the liver in the animals on the fat-free diet was elevated at 72 and 96 hr. The addition of either saturated or unsaturated fat in the diet at 48 hr prevented this accumulation. The total phospholipid and cholesterol concentrations of the liver were relatively uninfluenced by any diet in this study. Plasma total fatty acid concentration was elevated at 72 hr in the animals on a fat-free diet compared to those fed the stock diet, starved for 48 hr or fed the fat-containing diets. By 96 hr, however, plasma fatty acid concentrations in all groups were similar to those in animals fed only the stock diet. The release of de novo synthesized fatty acids into plasma from the liver was strongly inhibited by dietary fat, either saturated or polyunsaturated. With the fat-free diet there was a significant increase in the saturated and monounsaturated fatty acids in both liver and plasma.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Effect of prior nutritional status on the activity of lipogenic enzymes in primary monolayer cultures of rat hepatocytes.

Effect of prior nutritional status of the animal on the activity of lipogenic enzymes and the fatty acid content of cultured hepatocytes was investigated. Hepatocytes were isolated from rats that were starved for 24 h ('starved') or continuously fed ('fed'), or starved for 48 h and then re-fed for 48 h ('re-fed') with a carbohydrate-rich fat-free diet, and maintained as monolayer cultures for 96 h in a serum-free glucose-rich medium (Waymouth's MB752/1) supplemented with insulin, dexamethasone and tri-iodothyronine. The fatty acid content and the activities of acetyl-CoA carboxylase, fatty acid synthase, glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase were determined initially at 3 h after plating and then every 24 h. Initially the activities of all the four enzymes were highest in hepatocytes isolated from the re-fed rats and lowest in those from the starved rats. With time in culture, the activity of all these enzymes increased severalfold (2-5, depending on the enzyme under consideration) in hepatocytes isolated from fed and starved rats, whereas there was a severalfold (2-5) decrease in the activity of these enzymes in hepatocytes isolated from re-fed rats. The initial fatty acid content of the hepatocytes from re-fed rats was 2-3 times that in the other two groups of hepatocytes. The fatty acid content seemed to increase in all three groups of hepatocytes during the 96 h in culture, but these apparent increases were not statistically significant.

Acetyl-CoA Carboxylase↗
PubMed1986

Effect of nutritional status on the fatty acid composition of rat liver and cultured hepatocytes.

The lipid concentration and fatty acid composition of the whole liver and of cultured hepatocytes isolated from the livers of rats fed ad libitum (fed), fasted for 24 hr (fasted), or fasted for 48 hr and then refed a fat-free, high carbohydrate diet for 48 hr (refed) was studied. Hepatocytes were maintained as monolayer cultures in serum-free, lipid-free media and their fatty acid composition was analyzed at 3, 24, 48, 72 and 96 hr. The livers of fed animals, as well as their hepatocytes, contained less total lipid than those from animals on either of the other dietary regimes. Livers of fasted animals had three times the amount of lipid found in the livers of fed animals, and the livers of refed animals contained five times the amount of lipid as the livers of fed animals (all based on mg lipid/g wet weight of liver). The fatty acid composition of hepatocytes after 3 hr of culturing was very similar to that of fresh liver when compared in each of the dietary regimes. However, while the fatty acid compositions of livers and hepatocytes from fed and fasted animals were similar, the pattern in liver of refed animals was quite distinct from that of the fed animals. In the fed and fasted animals palmitic acid (16:0), stearic acid (18:0), oleic acid (18:1[n-9]), linoleic acid (18:2[n-6]) and arachidonic acid (20:4[n-6]) were the major fatty acids of the liver; in refed animals 16:0, palmitoleic acid (16:1[n-7]), 18:0, 18:1(n-9) and cis-vaccenic acid (the n-7 isomer of oleic acid) were the major fatty acids.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1980

Effect of cholesterol supplementation of diets of thyroidectomized dogs on the fatty acid composition of erythrocyte phospholipids and plasma phosphatidylcholine.

Thyroidectomized foxhounds were fed: (a) a control diet, (b) the control diet supplemented with 15% beef tallow or cottonseed oil, with or without added cholesterol, or (c) the control diet supplemented with beef tallow (15%), safflower oil (1.5%) and cholesterol. After 23 weeks on the diet, the content of the individual phospholipids of the erythrocytes was not altered appreciably. However, supplementing either the saturated (beef tallow) or polyunsaturated (cottonseed oil) diets with cholesterol produced similar changes in the fatty acid compositions of the phospholipid classes. Most consistently, there were increases in the percentages on 18:2 omega 6 and 20:3 omega 6 and decreases in the percentages of 20:4 omega 6 and 22:4 omega 6. Cholesterol supplementation of the diets similarly affected the fatty acid composition of phosphatidylcholine isolated from the platelet-free plasma of these animals.

Animals↗
PubMed1979

Effects of diets high in saturated fat and cholesterol on the lipid composition of canine platelets.

The phospholipid composition of platelets from dogs on various experimental diets was determined. Thyroidectomized foxhounds were fed a control diet or the control diet supplemented with (1) beef tallow, (2) beef tallow and cholesterol, or (3) beef tallow, cholesterol, and safflower oil for 23 weeks prior to isolation of platelets. Platelets from animals fed the control diet contained 36.7% phosphatidylcholine (PC), 22.8% phosphatidylethanolamine (PE), 18.4% sphingomyelin (Sph), 11.8% phosphatidylserine (PS), 6.3% phosphatidylinositol (PI), and 2.2% lysophosphatidylcholine. The PE was 77.6% in the plasmalogen form. No highly significant changes in the phospholipid class composition resulted from the experimental diets. Cholesterol supplementation of the diets, however, caused consistent alterations in the fatty acid compositions of the platelet phospholipids including increases in the percentages of 18:1 omega 9 (oleic acid), 18:2 omega 6 (linoleic acid), and 20:3 omega 6 (homo-gamma linolenic acid) and a decrease in the percentage of 20:4 omega 6 (arachidonic acid). Addition of safflower oil to the tallow-cholesterol diet partially reversed these effects. These cholesterol-induced alterations in fatty acid composition could be due to exchange with plasma lipids, de novo synthesis, or altered platelet metabolism. The mechanism remains to be determined.

Animals↗