Biomedical subjects

A H M Terpstra

Publications and source records attributed to A H M Terpstra.

7 recordsLinked to original sources

PubMed2007

The influence of dietary linoleic and alpha-linolenic acid on body composition and the activities of key enzymes of hepatic lipogenesis and fatty acid oxidation in mice.

We have recently suggested that feeding the C18 polyunsaturated fatty acid, alpha-linolenic acid (ALA), instead of linoleic acid (LA) reduced body fat in mice. However, the difference in body fat did not reach statistical significance, which prompted us to carry out this study using more animals and diets with higher contents of ALA and LA so that the contrast would be greater. The diets contained either 12% (w/w) LA and 3% ALA or 12% ALA and 4% LA. A low-fat diet was used as control. The diets were fed for 35 days. The proportion of body fat was not influenced by the type of dietary fatty acid. Plasma total cholesterol and phospholipids were significantly lower in ALA-fed mice than in mice fed LA. Activities of enzymes in the fatty acid oxidation pathway were significantly raised by these two diets when compared with the control diet. alpha-Linolenic acid vs. LA did not affect fatty acid oxidation enzymes. In mice fed the diet with LA activities of enzymes of de novo fatty acid synthesis were significantly decreased when compared with mice fed the control diet. alpha-Linolenic acid vs. LA feeding did not influence lipogenic enzymes. It is concluded that feeding mice for 35 days with diets either rich in LA or ALA did not significantly influence body composition.

Animals↗

PubMed2004

The effect of six different C18 fatty acids on body fat and energy metabolism in mice.

We studied the effects of five high-fat semi-purified diets varying at a 4% (w/w) level in either stearic, oleic, linoleic, alpha-linolenic, or gamma-linolenic acid on body fat and energy metabolism in BALB/c mice. A diet containing caprylic, capric, lauric, and myristic acid was used as a reference diet and a diet with 4% conjugated linoleic acid (CLA) was used as a positive control as it is known to effectively lower body fat in mice. The diets were fed for 35 d. Body fat was significantly lower in the CLA group than in the other groups but was not significantly different among the non-CLA groups. Among the non-CLA groups, the linoleic acid group tended to have the highest and the alpha-linolenic acid group the lowest proportion of body fat. In energy-balance studies, the percentage of energy intake that was stored in the body was significantly lower in the CLA group compared with the other dietary groups. The percentage of energy intake eliminated in excreta was highest in the stearic acid group followed by the gamma-linolenic acid group. These results were reflected in apparent fat digestibility, which was lowest in the stearic acid group. The percentage of energy intake expended as heat was highest in the CLA-fed mice. The results of the present study suggest that body fat and energy accretion in mice fed diets containing different C18 fatty acids is by far the lowest with CLA and that linoleic acid produced the highest fat intake and energy accretion.

Adipose Tissue↗

PubMed2003

Estimation of the proportion of body fat in mice from the proportion of body water.

We compared the proportion of body fat in mice as measured by chemical analysis with that estimated from the proportion of body water. First, we measured the proportion of fat by chemical analysis in 78 mice that had a proportion of body fat in the range from approximately 5 to 20%. Then, we constructed a regression line that described the relationship between the proportion of body water and the proportion of body fat by using data from several other published studies in mice (% body fat = -1.20 x % body water + 88.07, r = 0.9597, sy.x = 2.75, p < 0.001). With this regression line, we estimated the proportion of body fat from the proportion of body water that was measured by drying the carcasses at 60 degrees C for 3 days. Body fat data obtained from this regression line were similar to those obtained by chemical analysis. Thus, these results suggest that reliable values for the proportion of body fat can be derived from the proportion of body water and this method provides a tool to rapidly measure the proportion of body fat in mice.

Adipose Tissue↗

PubMed2003

Dietary conjugated linoleic acids as free fatty acids and triacylglycerols similarly affect body composition and energy balance in mice.

The objective of this study was to compare the effects of conjugated linoleic acid (CLA) as triacylglycerols (TAG) or free fatty acids (FFA) on body composition and energy balance in mice. We fed four groups of 5-wk-old Balb-C mice (n = 9) semipurified diets containing either CLA (0.5 g CLA/100 g of diet) or high oleic sunflower oil (HOSF) in the form of FFA or TAG for 42 d. Body composition was determined and the energy in the carcasses, excreta and food was measured in a bomb calorimeter. The amount of body fat was 4.72 +/- 0.95 g (17.9 +/- 2.8%) in the HOSF-FFA group, 2.36 +/- 0.29 g (9.4 +/- 1.0%) in the CLA-FFA mice (mean +/- SD, P < 0.05), 4.76 +/- 0.74 g (18.2 +/- 2.2%) in the HOSF-TAG group and 2.32 +/- 0.38 g (9.3 +/- 1.1%) in the CLA-TAG mice (P < 0.05). The percentage of energy intake that was stored in the body was 3.5 +/- 1.2% in the HOSF-FFA group, 0.6 +/- 0.3% in the CLA-FFA group (P < 0.05), 3.5 +/- 1.1% in the HOSF-TAG group and 0.5 +/- 0.4 in the CLA-TAG mice (P < 0.05). Conversely, the percentage of energy intake that was expended as heat was 89.4 +/- 1.2% in the HOSF-FFA group, 92.4 +/- 0.8% in the CLA-FFA mice (P < 0.05), 89.47 +/- 1.23% in the HOSF-TAG group and 92.2 +/- 0.4% in the CLA-TAG group (P < 0.05). Thus, CLA in the form of FFA or TAG had similar effects on body composition and energy balance.

Animals↗

PubMed2002

Intact pectin and its polygalacturonic acid regions have similar hypocholesterolemic properties in hybrid F1B hamsters.

We fed cholesterol-enriched (0.1% w/w) semipurified diets containing 3% of lemon pectin or 3% of the polygalacturonic acid regions fraction (smooth regions fraction) of the lemon pectin to hybrid F1B hamsters for a period of 8 weeks. A control group was fed cellulose and a positive control group was fed psyllium. The feeding of the semipurified diets resulted in an increase of plasma cholesterol levels in all the dietary groups when compared with initial values. The hamsters fed the psyllium, pectin, or the polygalacturonic acid regions fraction had significantly (P < 0.05) lower plasma cholesterol levels than the cellulose fed group throughout the experimental period. Plasma cholesterol levels in the hamsters fed the psyllium, pectin, or polygalacturonic acid regions fraction were not significantly different. Liver cholesterol concentrations were also lower in the hamsters fed the psyllium, pectin, or the polygalacturonic acid regions fraction than in the hamsters fed the cellulose, but this effect reached statistical significance only in the hamsters fed the polygalacturonic acid regions fraction. The results of these studies suggest that the polygalacturonic acid regions of the pectin molecule is responsible for the cholesterol-lowering properties of the pectin.

Animals↗

PubMed2002

The hypocholesterolemic effect of lemon peels, lemon pectin, and the waste stream material of lemon peels in hybrid F1B hamsters.

BACKGROUND: We found in preliminary studies with hamsters that citrus peels have a cholesterol lowering effect comparable to that of pectin extracted from these peels. AIM OF THE STUDY: We wanted to examine whether the cholesterol lowering effect of the peels could be completely accounted for by the pectin in the peels. METHODS: We fed cholesterol enriched (0.1 %,w/w) semipurified diets containing 3% (w/w) of cellulose, lemon peels, lemon pectin, and the waste stream material of the lemon peels to hybrid F1B hamsters for a period of 8 weeks. The waste stream of the lemon peels is the left over after extraction of the lemon pectin. RESULTS: Feeding the semipurified diets resulted in an increase of plasma cholesterol levels in all the dietary groups after 2 and 4 weeks on the diets. Cholesterol concentrations in the cellulose fed hamsters continued to increase after 4 weeks on the diet, whereas cholesterol levels in the other groups had reached a plateau. As a consequence, the plasma cholesterol levels in the hamsters fed the peels (5.59 +/- 0.74 mmol/L, mean +/- SD, n = 14), pectin (5.19 +/- 0.48 mmol/L), or waste stream (5.53 +/- 0.94 mmol/L) were lower than those in the hamsters fed cellulose (6.71 +/- 1.52 mmol/L) after 8 weeks on the diets. Differences in total plasma cholesterol were reflected in differences in both VLDL and LDL cholesterol concentration, but this effect was more distinct for the VLDL. There was no effect of the type of fiber on HDL cholesterol levels. Liver cholesterol concentrations paralleled. the concentrations of plasma cholesterol and the liver cholesterol concentrations in the hamsters fed the peels (3.57+/- 1.01 micromol/g liver, mean +/- SD, n = 14), pectin (4.86 +/- 1.42), and the waste stream (4.96 +/- 1.89) were lower than those in the cellulose group (7.19 +/- 2.32). The hamsters fed the peels, pectin, or waste stream tended to have a higher excretion of fecal bile acids and neutral sterols then the cellulose fed hamsters. CONCLUSION: The results of this study suggest that lemon peels and the waste stream of the lemon peels are as effective in lowering plasma and liver cholesterol in hamsters as the pectin extracted from the peels and that also compounds other than pectin are probably responsible for the cholesterol lowering effect of the citrus peels.

Analysis of Variance↗

PubMed2002

The decrease in body fat in mice fed conjugated linoleic acid is due to increases in energy expenditure and energy loss in the excreta.

We carried out energy balance studies in four groups of young, growing, 5-wk-old Balb-C mice (n = 12/group) that were either food restricted or nonrestricted and fed high fat diets (38 energy%) with or without 0.93 g/100 g conjugated linoleic acid (CLA) for 39 d. The energy in carcasses, excreta and food was measured in a bomb calorimeter. CLA lowered the percentage of the energy intake that was stored in the body from 1.9 +/- 0.8 to -2.3 +/- 0.7% (mean +/- SD, P < 0.05) in the nonrestricted mice and from 1.4 +/- 1.3 to -2.9 +/- 0.7% (P < 0.05) in the restricted mice. Thus, the CLA-treated mice had a net loss of body energy. The percentage of the energy intake eliminated in the excreta increased from 7.6 +/- 0.9% in controls to 8.7 +/- 1.0% (P < 0.05) in the CLA-treated mice that were nonrestricted and from 7.3 +/- 0.8 to 8.4 +/- 0.6 (P < 0.05) in the restricted mice. The amount of energy ingested minus the amount retained in carcasses and excreta equals the energy expenditure. The percentage of the energy intake that was expended as heat increased from 90.5 +/- 1.2 in controls to 93.6 +/- 1.5% (P < 0.05) in the CLA-treated nonrestricted mice and from 91.3 +/- 1.5 to 94.5 +/- 1.0% (P < 0.05) in the restricted mice. The lower energy storage in the CLA-fed mice was accounted for by an increase in the energy expenditure (74%) and by an increase in energy lost in the excreta (26%). Feeding CLA also increased liver weight, which may warrant further studies on the safety of CLA.

Adipose Tissue↗