Variations in daily intakes of myristic and a-linolenic acids in sn-2 position
modify lipid profile and red blood cell membrane fluidity
Henry Dabadie1*, Claude Motta2, Evelyne Peuchant3, Pascale LeRuyet4 and Franc¸ois Mendy5
1Service de Nutrition, Hoˆpital du Haut-Le´veˆque, Pessac, France
2Laboratoire de Biochimie me´dicale, Faculte´ de Me´decine, Rennes, France
3Laboratoire de Biochimie, Hoˆpital Saint-Andre´, Bordeaux, France
4Lactalis Recherche et De´veloppement, Re´tiers, France
5CNIEL, Paris, France
(Received 22 December 2005 – Revised 10 March 2006 – Accepted 20 March 2006)
The present study evaluated the effects of moderate intakes of myristic acid (MA), at 1·2% and 1·8% of total energy (TE), associated with a 0·9%
TE intake of a-linolenic acid (ALA) on lipid and fatty acid profiles and red blood cell membrane fluidity. Twenty-nine monks without dyslipidaemia
were enrolled in a 1-year nutritional study in which two experimental diets were tested for 3 months each: diet 1, MA 1·2% and ALA
0·9%; diet 2, MA 1·8% and ALA 0·9%. A control diet (MA 1·2%, ALA 0·4%) was given 3 months before diets 1 and 2. Thus, two different
levels of MA (1·2 %, 1·8%) and ALA (0·4 %, 0·9%) were tested. Intakes of other fatty acids were at recommended levels. Samples were obtained
on completion of all three diets. For fluidity analysis, the red blood cells were labelled with 16-doxylstearate and the probe incorporated the membrane
where relaxation-correlation time was calculated. Diet 1 was associated with a decrease in total cholesterol, in LDL-cholesterol, in triacylglycerols
and in the ratio of total to HDL-cholesterol; ALA and EPA levels were increased in both phospholipids and cholesterol esters. Diet 2 was
associated with a decrease in triacylglycerols and in the ratios of total to HDL-cholesterol and of triacylglycerols to HDL-cholesterol, and with an
increase in HDL-cholesterol; EPA levels were decreased in phospholipids and cholesterol esters. Red blood cell membrane fluidity was increased
in both diets (P,0·0001), but the higher increase was obtained with diet 1, mainly in the oldest subjects. Intakes of myristic acid (1·2 %TE) and
ALA (0·9 %TE), both mainly in the sn-2 position, were associated with favourable lipid and n-3 long-chain fatty acid profiles. These beneficial
effects coexisted with particularly high membrane fluidity, especially among the oldest subjects.
this seems like a negative for dairy fat, since this pathway is inferior to marine food (which bypasses delta6 desaturase enzyme altogether), but masks other detrimental aspects of dairy fat for 'typical' populations since they are likely deficient in w-3 fats. rather similar how k2 in cheese hides the harmful effects of other nutrients.
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