ALS (Amyotrophic Lateral Sclerosis) more commonly known as Lou Gehrig’s disease affects approximately 20,000 to 30,000 Americans, with another 5,000 patients diagnosed annually with the disease. It is a progressive, debilitating, neurological disease which attacks the neurons in the brain and spinal cord that control voluntary muscles. The eventual end result is paralysis.
Nutritional intervention has been shown to have a positive benefit on ALS patients, delaying the onset and even preventing the disease. The research published in the Annals of Neurology, specifies that increased consumption of foods containing colorful carotenoids, particularly beta-carotene and lutein, has a substantial impact on disease progression.
Carotenoids give fruits and vegetables their bright orange, red, or yellow colors, and are a source of dietary vitamin A. Researchers also examined vitamin C’s role as an antioxidant and its relation to ALS risk.
“ALS is a devastating degenerative disease that generally develops between the ages of 40 and 70, and affects more men than women,” said senior author Dr. Alberto Ascherio, Professor of Epidemiology and Nutrition at Harvard School of Public Health in Boston, Mass. “Understanding the impact of food consumption on ALS development is important. Our study is one of the largest to date to examine the role of dietary antioxidants in preventing ALS.”
The data for the research was compiled from five prospective groups: the National Institutes of Health (NIH)–AARP Diet and Health Study, the Cancer Prevention Study II-Nutrition Cohort, the Multiethnic Cohort, the Health Professionals Follow-up Study, and the Nurses’ Health Study, researchers investigated more than one million participants for the present study. A total of 1093 ALS cases were identified after excluding subjects with unlikely food consumption.
The team found that a greater total carotenoid intake was linked to reduced risk of ALS. Individuals who consumed more carotenoids in their diets were more likely to exercise, have an advanced degree, have higher vitamin C consumption, and take vitamin C and E supplements. Furthermore, subjects with diets high in beta-carotene and lutein—found in dark green vegetables—had a lower risk ALS risk. Researchers did not find that lycopene, beta-cryptoxanthin, and vitamin C reduced the risk of ALS. Long-term vitamin C supplement intake was also not associated with lower ALS risk.
Dr. Ascherio concludes, “Our findings suggest that consuming carotenoid-rich foods may help prevent or delay the onset of ALS. Further food-based analyses are needed to examine the impact of dietary nutrients on ALS.”
In another study that suggests that oxidative stress plays a large role in the development of ALS, smoking and ALS have been linked by a research team led by Hao Wang, M.D., Ph.D., of the Harvard School of Public Health, Boston. The scientists analyzed data from five different long-term studies involving a total of more than 1.1 million participants, of whom 832 had ALS.
The study found that there was an increased risk of developing ALS by smokers vs non smokers. In addition the rates of ALS in the five studies combined increased with age and with the number of packs per year smoked, and were higher in men than women for all age groups. Current smokers had a 42 percent increased risk of developing the disease and former smokers had a 44 percent increased risk.
The risk of developing ALS increased by 10 percent for each increment of ten cigarettes smoked per day and by 9 percent for each 10 years of smoking; however, these associations did not persist when never-smokers were excluded. Among those who smoked, the risk of ALS increased as the age they started smoking decreased.
“Several possible mechanisms by which cigarette smoking might influence the risk of ALS have been suggested, including direct neuronal damage from nitric oxide or other components of cigarette smoke (such as residues of pesticides used in tobacco cultivation) or from oxidative stress,” the authors write. “Chemicals that are present in cigarette smoke generate free radicals and products of lipid peroxydation, and smokers have a higher turnover of the major antioxidant vitamin C. Exposure to formaldehyde, a by-product of the combustion product of tobacco smoking, was reported in 2008 to be associated with an increased risk of ALS.”
H. Wang, E. J. O’Reilly, M. G. Weisskopf, G. Logroscino, M. L. McCullough, M. J. Thun, A. Schatzkin, L. N. Kolonel, A. Ascherio. Smoking and Risk of Amyotrophic Lateral Sclerosis: A Pooled Analysis of 5 Prospective Cohorts. Archives of Neurology, 2011; 68 (2): 207 DOI: 10.1001/archneurol.2010.36
Kathryn C Fitzgerald, Éilis J O’Reilly, Elinor Fondell, Guido J Falcone, Marjorie L McCullough, Yikyung Park, Laurence N Kolonel, Alberto Ascherio. Intakes of vitamin C and carotenoids and risk of amyotrophic lateral sclerosis: Pooled results from 5 cohort studies. Annals of Neurology, 2012; DOI: 10.1002/ana.23820