Omega-3, Vitamin D and Sunlight

Omega-3, Vitamin D and Sunlight: "Essential Fats for Humans
Fatty acids play critical roles in human health and disease. Cell membranes (all cells) are composed of a double layer of fats. Your brain is about 60% fat. The fats you eat strongly influence the ability of your cell membranes, especially brain and nerve cells, to function.
Cholesterol is an alcohol, not a fat. Natural saturated fats are found in all foods to some degree. Saturation of a fat may be natural or from processing as is done to make margarine solid. Naturally occurring saturated fats are not associated with disease unless they are imbalanced by inadequate intake of the polyunsaturate essential fatty acids, especially the omega-3 fats.
Linoleic Acid is an omega-6 that is 20 (or more) times too high in the American diet and strongly implicated in degenerative diseases.
Linolenic Acid is a short chain omega-3 found in perilla, canola and flax considered by some to be important as a source of long chain omega-3 DHA and EPA but many Americans suffer from poor conversion, an enzyme insufficiency, or impaired genetic ability to elongate the fatty acid to its active EPA and DHA forms.
Arachidonic Acid is found in meat and fish and eggs and dairy and made in our bodies from linoleic acid. It is critical for the growth of the body and brain and for healthy immune function but is needed in very small amounts.
EPA, eicosapentanoic acid and DHA, docosahexaenoic acid, are found in fish, grass-fed beef and poultry and wild game. Some may be made from linolenic acid, depending on your genetics, your liver function and other as yet unknown factors."