Antioxidants & Dementia Risk – A New Study in Neurology

May A. Beydoun, PhD, MPH of the National Institute on Aging of the NIH in Bethesda, Maryland and associates published a study on blood antioxidant levels, food consumed and the risk of developing dementia as you aged. The study hoped to determine which foods were best to eat to limit your chances of developing cognitive impairment in later years. The researchers discovered that those individuals with the highest serum levels of lutein+ zeaxanthin and beta-cryptoxanthin at baseline were less likely to develop dementia decades later than their peers with lower levels of these protective antioxidants.

Lutein and zeaxanthin are found in green leafy vegetables such as kale, spinach, broccoli, and peas. Beta -cryptoxanthin is found in fruits such as oranges, papaya, tangerines, and persimmons. “Antioxidants may help protect the brain form oxidative stress, which can cause cell damage,” said lead author Dr. Beydoun.

The study, published in the journal Neurology analyzed 7,283 participants in the 3rd National Health and Nutrition Examination Survey who were at least 45 years old at the start of the study and were then followed for 16-17 years. The data showed the higher the serum levels of beta-cryptoxanthin at baseline the lower the risk of developing dementia. No such protection was found for lycopene, alpha-carotene, beta carotene or Vitamins A, C, or E.

This was an observational study looking at data already collected. In critiquing the study, Dr B. Hooshmand, MD, PhD and Milia Kiviipelto, MD, PhD of the Karolinska Institute, Stockholm, Sweden commented on the research noting that this was an observational study and previous studies supplementing individuals with antioxidants were disappointing and did not prevent development of cognitive dysfunction. They believe there is a more complex relationship between the foods we eat, antioxidants, socioeconomic status and lifestyle which all contribute to the development of dementia.

While there is work to be done in this field, this study certainly supported my love for a fresh orange or tangerine to start off the day. The accompanying editorial made it clear that consuming my antioxidants and vitamins in fresh fruit and produce seems to be healthier than depending on store purchased supplements.

More Anti-Oxidants Provide No Benefit for Aging Eyes

Two papers presented at the Association for Research in Vision (ARVO) conference in Seattle emphasized that in a population of patients with adequate nutrition the addition of more antioxidants, vitamins and supplements do not help your vision or prevent progression or development of eye disease. In fact, not only did they not help but there was a significant concern that the addition of lutein and beta carotene to the diet of smokers and former smokers actually increased the risk of those individuals developing carcinoma of the lung. The studies were published in JAMA Ophthalmology and the Journal of the American Medical Association.

The study, known as Age-Related Eye Disease Study 2 (AREDS2), concluded that adding lutein, zeaxanthin, and fish oil to daily multivitamin supplements does not boost prevention of age related macular degeneration or cataracts in high risk individuals.

The original AREDS study showed that adding high doses of Vitamin C and Vitamin E, beta carotene and zinc slowed and lowered progression of early and intermediate age related macular degeneration and associated vision loss. That original study suggested that the addition of more antioxidants might help. This was the basis for the follow-up study AREDS2.  The follow up study randomized patients to receive lutein plus zeaxanthin, or omega 3 fatty acids, plus DHA and EPA, both, or a placebo. No benefit of adding these antioxidants was noted except in patients with extreme nutritional deprivation situations.

Vitamin C is a water soluble vitamin.  You keep what you need and the rest is eliminated harmlessly through the kidneys. Vitamin E is a fat soluble vitamin and excess intake is stored in the cells of your body.  Toxicity can occur from ingesting too much of Vitamin E or Vitamin A.  Beta Carotene has been postulated to have an effect on lung cancer in other studies.   The bottom line, too much of anything is not good for you. 

Patients should be asking their ophthalmologists about the constituents of the supplements being recommended to them for eye health.  If they are a cigarette smoker or former smoker they should question the need for beta carotene and lutein because of the association with lung cancer. They should review their total Vitamin A, E, D and K intake from their ophthalmologic vitamins and supplements and their other vitamins and supplements to insure that their total daily intake does not exceed recommended levels.