Dr. Grossman’s Blog

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A study published in the Nutrition Journal sought to find how walnuts can increase the plasma antioxidant capacity of healthy adults.  Study authors did not find any measurable increases, but they believe that further study is warranted.

They did find that levels of important compounds, the fatty acid linoleic acid and pyridoxal phosphate (vitamin B6), did increase over the course of the 19 week study.

Source: http://www.nutritionj.com/content/9/1/21

Antioxidants are a key to eye health. They combat free radials that cause such eye diseases, particularly macular degneration and cataracts.

Researchers have released a new study showing that regular consumption of fish, omega-3 polyunsaturated fatty acids, and nuts helps protect against age-related macular degeneration (AMD).

The study, published in the Archives of Ophthalmology, assessed the relationship between dietary fatty acids and the 10-year incident of AMD.

Scientists examined 3654 elderly Australian participants at baseline and re-examined 2454 of these participants five and/or ten years later.  Participants completed a food frequency questionnaire.

The findings confirmed many previous studies on AMD.  After adjusting for age, sex, and smoking:

• one serving of fish per week was associated with reduced risk of early AMD primarily among participants with less than the median linoleic acid consumption
• findings were similar for consumption of long-chain omega-3 polyunsaturated fatty acids:  one to two servings of nuts per week was associated with reduced risk of early AMD 
• protective associations between nut consumption and reduced risk of pigmentary abnormalities were seen among nonsmokers, participants with less than the median ratio of serum total to high-density lipoprotein cholesterol, and those with beta carotene intake greater than the median level.

This study provides evidence of protection against early AMD through:

• regular consumption of fish and nuts
• greater consumption of omega-3 polyunsaturated fatty acids
• low intakes of foods rich in linoleic acid

Read more about AMD and natural eye care

Learn which foods to eat to help maintain good eye health

SOURCE:  Dietary Fatty Acids and the 10-Year Incidence of Age-Related Macular Degeneration, The Blue Mountains Eye Study, Tan, et al, Arch Ophthalmol. 2009;127(5):656-665.

A recent study shows that consumption of omega-6 fatty acid may help alleviate dry eye symptoms and improve overall lens comfort in patients suffering from contact lens-associated dry eye.

Researchers evaluated the effects of oral treatment with omega-6 fatty acids in the form of evening primrose oil (EPO) on subjective symptoms, ocular surface signs and tear film characteristic in patients with contact lens-associated dry eye.

76 female soft contact lens wearers were treated for six months either with omega-6 fatty acids in the form of EPO or placebo (olive oil). The patients were given three examinations (baseline, three and six months) to test tear film characteristics (tear meniscus height, break-up time), meibomian gland function (lipid layer thickness and quality) and ocular surface parameters (hyperemia and staining). At each examination the women were given a questionnaire relating to lens comfort and dry eye symptoms.

The EPO group showed a significant improvement in the specific symptom of “dryness” at three and six months as well as a significant improvement in overall lens comfort at six months. Tear meniscus height was increased in the EPO group at six months relative to baseline, although all other objective signs were unchanged.

These findings support a 2003 study on omega-6 fatty acids which evaluated the effect of systemic linoleic acid (LA) and gamma-linolenic acid (GLA) on patients with dry eyes.

GLA is an essential fatty acid in the omega-6 family that is found primarily in plant-based oils, such as evening primrose oil, black currant seed oil, and borage seed oils. Essential fatty acids help the body’s natural ability to fight inflammation, but cannot be made in the body and must be obtained from food. LA, another omega-6 fatty acid, is found in plant oils such as safflower oil and is converted to GLA in the body.

In a randomized clinical trial, 26 patients with dry eye (aqueous-deficient keratoconjunctivitis sicca) were randomly divided into two groups of 13 patients each. The study group received tablets containing LA (28.5 mg) and GLA (15 mg) twice daily for 45 days; the control group received a placebo tablet for 45 days.

The results? Researchers found that therapy with LA and GLA and tear substitutes reduced ocular surface inflammation and improved dry eye symptoms.

Read more about dry eye and studies on dry eye

SOURCE: Oral Omega-6 Essential Fatty Acid Treatment in Contact Lens Associated Dry Eye. Kokke, et al. Cont Lens Anterior Eye 2008;31(3):141-6.

SOURCE: Systemic Linoleic and Gamma-Linolenic Acid Therapy in Dry Eye Syndrome With an Inflammatory Component, Barabino, et al.Cornea. 22(2):97-101, March 2003.