| 21. |
- Saltin, Bengt, et al.
(författare)
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Free fatty acids and exercise.
- 1993
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Ingår i: American Journal of Clinical Nutrition. - 0002-9165 .- 1938-3207. ; 57:5 Suppl, s. 752S-757S; discussion 757S
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Tidskriftsartikel (refereegranskat)abstract
- Although the great explorers were well aware that eating fat was an efficient way to meet their large energy demand, it was not until some decades into this century that it could be demonstrated that lipids are metabolized directly by contracting skeletal muscles. The 1950s produced the first studies with [14C]-tagged fatty acids (FAs), proving that fat is transported into the cell as FAs. An FA-transporting protein that is present in the sarcolemma and in the cytoplasma has been identified. For FA transport into the mitochondria, carnitine and carnitine transferase are needed. It is still unclear how the use of lipids as an energy source for the muscle during exercise is limited. The supply of free fatty acids (FFAs) far exceeds what is taken up by the muscle. Seldom more than 2-4% of the amount of FFAs delivered to an exercising limb is taken up by the muscles and only part of it is oxidized. Physical training induces changes that enhance the uptake of FAs by the contracting muscles, and a larger fraction of this uptake is oxidized, but it is not yet clear which mechanism is behind this adaptation. What is known is that this uptake occurs despite no elevation in the amount of FA supplied to the limb.
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| 22. |
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| 23. |
- Sandberg, Ann-Sofie, et al.
(författare)
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Alginate, small bowel sterol excretion, and absorption of nutrients in ileostomy subjects
- 1994
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Ingår i: American Journal of Clinical Nutrition. - 0002-9165 .- 1938-3207. ; 60:5, s. 751-756
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Tidskriftsartikel (refereegranskat)abstract
- The effect of alginate on ileostomy excretion of sterols and nutrients was investigated in six ileostomy subjects fed a constant low-fiber diet with or without supplementation with 7.5 g sodium alginate. A mean of 95% of uronic acids derived from the sodium alginate was recovered in the ileostomy contents. Supplementation with alginate increased fat excretion by 140% and decreased bile acids excretion by 12%. Sodium and potassium excretion were significantly increased whereas starch and nitrogen excretion were unchanged. Five of six subjects showed a decreased apparent absorption of iron and manganese with alginate, which, however, was not statistically significant. Absorption of phosphorus, calcium, magnesium, and zinc were unchanged. Almost no digestion of sodium alginate occurs in the stomach and small intestine. The increased fatty acids excretion may be explained by the binding or trapping of fatty acids in the gel matrix formed by alginate, which may also cause a reduced bile flow.
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| 24. |
- Smedman, A E, et al.
(författare)
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Pentadecanoic acid in serum as a marker for intake of milk fat : relations between intake of milk fat and metabolic risk factors.
- 1999
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Ingår i: American Journal of Clinical Nutrition. - : Elsevier BV. - 0002-9165 .- 1938-3207. ; 69:1, s. 22-9
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The fatty acid composition of the diet is known to be partially reflected by the fatty acid composition of serum lipids.OBJECTIVE: We examined whether pentadecanoic acid (15:0) in serum lipids can be used as a marker for intake of milk fat, the major dietary source of 15:0. We also investigated the relations between intake of milk fat and cardiovascular disease risk factors.DESIGN: Sixty-two 70-y-old men completed 7-d dietary records. The intake of milk products was studied in relation to the proportions of 15:0 in serum cholesterol esters and phospholipids, as well as to the clinical characteristics of these men, by using Spearman's rank correlation.RESULTS: The proportions of 15:0 in serum cholesterol esters were positively related to butter intake (r = 0.36. P = 0.004) and to the total amount of fat from milk products (r = 0.46, P < 0.0001): 15:0 in phospholipids was related to the amount of fat from milk and cream (r = 0.34, P = 0.008) and to the total amount of fat from milk products (r = 0.34, P = 0.008). Inverse associations were found between intake of milk products and body mass index, waist circumference, LDL-HDL ratio, HDL triacylglycerols, and fasting plasma glucose, whereas relations to HDL cholesterol and apolipoprotein A-I tended to be positive.CONCLUSIONS: The results suggest that 15:0 in serum can be used as a marker for intake of milk fat. The explanation for the inverse associations between the intake of milk products and certain cardiovascular risk factors is not known.
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