This study explains the possible link between saturated fats and inflammatory processes which are linked to several diseases. Note that it is not so much the fat itself but the ratio of "bad fats" to good fats.
For the past century, changes in the Western diet have altered the consumption of omega-6 fatty acids (w6, found in meat and vegetable oils) compared with omega-3 fatty acids (w3, found in flax and fish oil). Many studies seem to indicate this shift has brought about an increased risk of inflammation (associated with autoimmunity and allergy), and now using a controlled diet study with human volunteers, researchers may have teased out a biological basis for these reported changes.
Anthropological evidence suggests that human ancestors maintained a 2:1 w6/w3 ratio for much of history, but in Western countries today the ratio has spiked to as high as 10:1. Since these omega fatty acids can be converted into inflammatory molecules, this dietary change is believed to also disrupt the proper balance of pro- and anti- inflammatory agents, resulting in increased systemic inflammation and a higher incidence of problems including asthma, allergies, diabetes, and arthritis.
Floyd Chilton and colleagues wanted to examine whether theses fatty acids might have other effects, and developed a dietary intervention strategy in which 27 healthy humans were fed a controlled diet mimicking the w6/w3 ratios of early humans over 5 weeks. They then looked at the gene levels of immune signals and cytokines (protein immune messengers), that impact autoimmunity and allergy in blood cells and found that many key signaling genes that promote inflammation were markedly reduced compared to a normal diet, including a signaling gene for a protein called PI3K, a critical early step in autoimmune and allergic inflammation responses.
Relating to the previous post, the balance of these fats is significantly altered in a positive direction when animals are freely pastured, eat a natural diet of grass, and treated humanely. Eat grass fed beef whenever possible and make sure to eat cold water fish twice a week. Non meat-eaters and meat eaters can also use free-range eggs, brussel sprouts, nuts, and flax seed as a natural supplement, or take three fish oil capsules a day. Note: inflammation is also related to CAD (coronary artery disease).