Essential fatty acids and GLA
GLA helps atopic dermatitis (eczema)
EPA/DHA and GLA in acne patients
EPA/DHA and GLA for dry eye syndrome
GLA+ALA for back pain and neuropathy
Leafy greens lower glaucoma risk
Dietary fats include saturated and unsaturated fats. Unsaturated fats are generally liquid (oils) and saturated fats are solid. Mono-unsaturated fats (such as olive oil) may be liquid or solid depending on the storage temperature. Artificially saturated fats (partially hydrogenated vegetable oils) contain damaging substances called “trans” fats, which do not occur naturally.
Some fats are required in the diet, as they are essential for health but they are not made in the body. They stimulate hair and skin growth, are important for bone health, control metabolism, and support reproductive function. Most people consume far too much fat, but unfortunately, in addition to the health risks from too many calories, it is often highly processed and lacking in adequate amounts of the essential fatty acids.
The essential dietary fats include those called omega-3 and omega-6. They are also known as polyunsaturated fatty acids (PUFA). Flaxseeds, walnuts, and soybeans are rich sources of the omega-3 oil “alpha-linolenic acid” (ALA) which is a precursor to EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid). EPA and DHA are found naturally in oily fish such as sardines and salmon, and they are also made in the body from the ALA, assuming that your enzymes are active. These omega-3 byproducts can reduce inflammation.
The omega-6 fatty acid (cis-linoleic acid, or cLA) is found in many nuts and seeds (such as flax, sunflower, and sesame) as well as corn and soybeans. Again, many of the commercial oils are highly processed, rendering the oils less nutritious. In the human body, cLA is converted to gamma-linolenic acid (GLA). The conversion process depends on enzymes (just like the EPA and DHA conversion), but with age, disease, nutritional deficiencies, and other conditions these enzymes may be less active, impairing the production of all of these substances and the regulatory molecules into which they are made.
Recent research has confirmed some of the earlier work on the specific benefits of supplemental GLA, a precursor of the anti-inflammatory prostaglandins (including PGE1and others). GLA is found in evening primrose seed oil, borage seed oil, and black currant seed oil, and these are all available as dietary supplements. These can be helpful in treating or preventing chronic inflammation, eczema, dry eye syndrome, asthma, diabetes, and arthritis. Chronic inflammation itself is suspected of contributing to causing diseases such as atherosclerosis, dementias, diabetes, Parkinson’s disease, and cancer.
The anti-inflammatory action of GLA supplements helps in the prevention and treatment of rheumatoid arthritis, psoriasis, and eczema. Related effects help to dilate blood vessels to improve circulation and decrease the adhesiveness of platelets (for which some people take aspirin or other drugs). GLA can also improve nerve conduction in diabetics, reducing paresthesias (numbness and tingling). (Kapoor R, Huang YS, Gamma linolenic acid: an antiinflammatory omega-6 fatty acid. Curr Pharm Biotechnol. 2006 Dec;7(6):531-4.) Earlier studies have shown benefits of GLA supplements for asthma and rheumatoid arthritis.
Evening primrose oil contains about 40 mg of GLA per 500 mg capsule. In a study of atopic dermatitis (also known as eczema) 21 subjects were given 320 to 480 mg of GLA as 4000 to 6000 mg of evening primrose oil. They received treatment for 12 weeks, and they were assessed for symptoms at the start of the study and at 4 and 12 weeks using a rating scale called SCORAD. The researchers also measured the plasma levels of GLA and one of its metabolites, DGLA.
At both the 4- and 12-week evaluations, plasma levels of GLA and DGLA were increased. These levels correlated with a significantly reduced symptom score. This was only a pilot study, as there was no control group, but the results are similar to what had been found previously (I first learned about it in 1982). However, not all studies have supported this conclusion. It is possible that the response to GLA varies from person to person, accounting for the variability in the studies. Essential fatty acids are required for healthy cell membranes, including skin cells. (Simon D, et al., Gamma-linolenic acid levels correlate with clinical efficacy of evening primrose oil in patients with atopic dermatitis. Adv Ther. 2014 Feb;31(2):180-8.)
GLA from any source is a valuable supplement, especially for those with a variety of chronic conditions. Essential fatty acid deficiency replicates the symptoms of atopic dermatitis. I often recommend 240 to 360 mg of GLA per day, most commonly from borage oil, as it is more concentrated than evening primrose oil so you can take just one capsule to get the same dose as six capsules of evening primrose oil.
Korean researchers designed a study to evaluate the effects of a combination of EPA/DHA or GLA in the treatment of acne. In this study, 45 patients with mild to moderate acne vulgaris were randomized to take either omega-3 fatty acids (2,000 mg of combined EPA and DHA), gamma-linolenic acid (borage oil containing 400 mg of GLA), or a control group. They were followed for 10 weeks.
After 10 weeks, both the EPA/DHA and the GLA groups showed a significant reduction in both inflammatory and non-inflammatory acne lesions. The patients’ own evaluation of their improvement showed a similar result compared with the control group. In addition to the subjective evaluations, tissue examination with cellular staining showed reductions in inflammation and lower levels of inflammatory chemicals. No adverse effects were noted in any of the subjects. (Jung JY, et al., Effect of dietary supplementation with omega-3 fatty acid and gamma-linolenic acid on acne vulgaris: a randomised, double-blind, controlled trial. Acta Derm Venereol. 2014 Sep;94(5):521-5.
For any inflammatory disorders GLA and EPA/DHA would be beneficial, usually in the doses listed in this article. For those who prefer to avoid animal products, consuming flaxseed oil and walnuts will provide some omega-3 oils, but with the caution that the conversion to EPA/DHA might be inadequate to provide the desired benefits. Acne is particularly distressing to young people, and it is usually partly the result of inadequate nutrition. When I first traveled to Japan in 1999, I saw hardly anyone with acne or acne scars. On subsequent trips, and especially my last trip 10 years later, I noted both the dramatic expansion of fast-food chains and an increase in the prevalence of acne.
Another study of combined GLA plus EPA/DHA showed benefits for post-menopausal patients with dry eye syndrome (keratoconjunctivitis sicca). Dry eye is also seen with age and some inflammatory autoimmune conditions. In this study, 38 patients with tear dysfunction were randomized to receive either a combination of GLA and EPA/DHA or a placebo for six months. At the start of the study they were evaluated with a number of tests, including the Ocular Surface Disease Index, the Schirmer test (for tear production), and corneal smoothness. They were then assessed again at 4, 12, and 24 weeks.
After 24 weeks, the Ocular Surface Disease Index score improved (was lower) with the supplementation, with a score of 21, compared to the placebo group, with a score of 34. In addition, the surface asymmetry index was significantly lower in the supplement-treated group (0.37 versus 0.51). Neither treatment had any effect on tear production or the staining tests of the cornea or conjunctiva. (Sheppard JD Jr, et al., Long-term supplementation with n-6 and n-3 PUFAs improves moderate-to-severe keratoconjunctivitis sicca: a randomized double-blind clinical trial. Cornea. 2013 Oct;32(10):1297-304.)
Dry eye is seen with a condition called Sjogren’s syndrome, an autoimmune inflammatory disease, but also as an independent problem. Supplementing with these essential fatty acids may well help reduce symptoms because of their anti-inflammatory effects. GLA also helps immune function through its effects on prostaglandins. Again, the typical dose of GLA is 240 to 360 mg per day, and common doses of omega-3 fatty acids are 1000 to 2000 mg daily.
Compression of spinal nerves by collapsing vertebral discs can lead to back pain and neuropathy. Sometimes after a precipitating accident, the inflammation can lead to chronic syndromes that become disabling. In a study of 203 patients, all were treated with a physical rehabilitation program and half were also treated with oral doses of 600 mg of alpha-lipoic acid (ALA) plus 360 mg of gamma-linolenic acid (GLA). They were examined at the start of the study and again at 2, 4, and 6 weeks.
They were evaluated with a Low Back Pain Disability questionnaire, the Aberdeen Low Back Pain Scale, and a quality of life questionnaire (SF36), as well as other disability questionnaires. They were also evaluated for the level of paresthesias (numbness and tingling), and stabbing and burning pain. At the end of the study, the researchers noted significant improvements in symptoms as well as all of the specific measurement scales. The combination therapy with GLA plus ALA provided significantly better outcomes than the rehabilitation program alone. (Ranieri M, et al., The use of alpha-lipoic acid (ALA), gamma linolenic acid (GLA) and rehabilitation in the treatment of back pain: effect on health-related quality of life. Int J Immunopathol Pharmacol. 2009 Jul-Sep;22(3 Suppl):45-50.)
Alpha-lipoic acid is known to help with diabetic peripheral neuropathy, usually in doses of 1000-1200 mg per day. Adding GLA to the treatment may help by improving nerve conduction velocity and acting as an anti-inflammatory. The usual dose is 240 to 480 mg of GLA per day.
Eating a lot of all vegetables is very healthful, and new evidence suggests that high dietary intake of leafy green vegetables, in addition to its other benefits, can lower the risk of glaucoma. Glaucoma is a condition of high pressure inside the eye leading to damage to the optic nerve and loss of vision, especially peripheral vision. It is commonly seen with aging. In early stages it is asymptomatic, so regular eye exams are needed to have the eye pressures tested in order to catch it early before loss of vision occurs. Treatment is usually with topical medications in the form of eye drops, although these can have side effects. As with many other conditions, prevention is preferable.
Nitric oxide is a chemical in the blood and tissues that helps to relax blood vessels. It is produced from nitrates by the endothelial cells that line the arteries. In addition to relaxation of the retinal blood vessels, it appears to influence the outflow of fluid in the eye, helping to reduce the internal pressure. Dietary sources of nitrates can contribute to an increase of this relaxing factor in the tissues. Leafy greens are one source of dietary nitrates.
This new study evaluated data from 63,893 women from the Nurses’ Health Study and 41,094 men from the Health Professionals Follow-up Study. The participants were 40 years or older, had no glaucoma at the start of the study, and they were evaluated every two years for 26 to 28 years. Information on diet was based on validated questionnaires.
Compared to those with the lowest intake of nitrates, primarily from leafy green vegetables, those with the highest intake had a 21 percent lower risk of developing glaucoma. The reduced risk of loss of central vision was even more striking than for peripheral vision, with a 44 percent reduction. Green leafy vegetable intake accounted for 57 percent of the variation in nitrate consumption. (Kang JH, et al., Association of dietary nitrate intake with primary open-angle glaucoma: a prospective analysis from the Nurses' Health Study and Health Professionals Follow-up Study. JAMA Ophthalmol. 2016 Jan 14:1-11.)
I think all health professionals, whatever their dietary persuasion, would agree that green vegetables, including leafy greens, are a healthful part of the diet. Now we have evidence (although not a proven cause-and-effect relationship) that they are valuable for preservation of vision. Leafy green vegetables include spinach, kale, collards, mustard greens, dark green lettuces, Swiss chard, broccoli, and watercress, among others. In addition to the nitrates that they contain, greens are valuable for their content of the carotenoids lutein and zeaxanthin, which are also important for vision preservation. Lutein and zeaxanthin are the only carotenoids found in the retina and lens of the eye. They can help prevent macular degeneration and cataracts.