Asthma, Allergies and Nutrition - The Story Part IX
April 15th, 2019
THE NUTRITIONAL STUDIESTHE DO Omega 3 and 6 Fatty Acids
Fish oil, flax oil, wild caught fish, kelp, grass fed meats are all the rage now for health conscious consumers. There is good reason for this shift in consumerism. These foods are all loaded with health promoting omega three fats. On the other hand, seed and vegetable oils are the major source of omega six fatty acids. Omega three and six fatty acids are a type of fat called polyunsaturated fatty acid(PUFA)
which in chemistry terms means that there are at least two or more double bonds located on the carbon chain. This piece of information is important because this chemical structure makes it more unstable when exposed to heat, oxygen or chemicals, which in turn can on occasion make the fatty acid unhealthy.
Mechanistically, omega three and six fats are used by the body in cell membranes and as a precursor for a chemical pathway called prostaglandins which are pro and anti inflammatory chemicals released during injury, infection and repair. It is commonly understood that omega three fats are the precursor foods for the anti-inflammatory cascade while omega six fats are on the other side of the equation promoting inflammation. They share a set of enzymes in their conversion to their beneficial end products and are both necessary in moderation.
During my training in Arizona with Dr. Weil, we were taught that historically, it was believed that humans consumed roughly a 3:1 ratio of omega 6:3 fats. Currently, it is more akin to 30:1 based on the voluminous rise in processed foods with seed and vegetable oils. Based on this change in substrate ratios, we would assume that the flood of omega six fats would push the prostaglandins equation toward increased inflammation.
Based on the mechanisms and natural logic, it would seem prudent that following the older paradigm of a 3:1 ratio of PUFA's would hold benefit for reducing inflammation in asthmatics. However, the data regarding asthma and supplementing PUFA's is mixed at best. Dr. Julia's Nature Reviews article has a nice summary of the effects at the biochemical level for inflammation.
In two recent reviews of the current data, supplementation with fish oil/omega three fats was neutral in benefit. (Muley et. al. 2015)(Kwok et. al. 2017)
Boiling it all down: I resolve to follow the fish. Humans for thousands of years ate more fish and less to no omega 6 oils. It is highly likely that a 3:1 ratio of 6:3 PUFA's is more in line with human physiology. Mechanistically, this makes complete sense.
I recommend that all of my asthmatic patients reduce the volume of processed food which is the major human source of refined omega 6 oils. I further recommend that asthmatic children eat more small oily fish like mackerel, sardines, salmon. Taking fish oil as a supplement is safe and may turn out to be helpful although that remains to be seen.
Balancing the PUFA ratio is key in my mind.
The story wraps up next week,
Julia Nature Reviews Immunology Article
Muley Journal of Allergy Article
Kwok Thorax Article