Anti-oxidants

From Ganfyd

Generically, any chemical compounds that resist oxidation. In medicine, this usually refers to chemical compounds in food.

Purported health benefits on the basis that they scavenge free radicals and prevent oxidative damage of tissues, which in turn may have benefits in preventing ageing, cancer and atherosclerotic disease.

Cardiovascular Disease

Atherosclerosis is the key pathological process in heart disease. In the response-to-injury hypothesis, atherosclerosis is a chronic inflammatory response to damage to the blood vessel wall. Endothelial cells interact with other cell types such as smooth muscle cells and macrophages. Complex interactions between these cells and components in the blood such as platelets and low-density lipoprotein (LDL) lead to formation of an atheromatous plaque, the lesion responsible for the clinical manifestations of heart disease.

Of particular interest in the atherosclerotic process has been the uptake and subsequent oxidation of LDL by macrophages. According to the 'oxidative-modification' hypothesis, oxidation of LDL modifies its biological properties, which initiate and exacerbate the development of atheroma. The rationale behind anti-oxidants is that retardation of the oxidative process could also halt or attenuate the process of atherosclerosis. Dietary epidemiology is consistent leading to studies of selective supplimentation. This generally has failed to work leading to the conclusion that anti-oxidant supplementation is likely to be ineffective or harmful in real life in multiple large trials in Western populations.^[1][2]. Positive results may be confined to subpopulations with nutritional deficiency for cultural or other reasons.^[3]

Mortality

Perhaps more important than specific anti-oxidant benefit is that meta-analysis suggests mortality may be increased in those who take anti-oxidant supplementation for whatever reason.

• Vitamin A likely to be ineffective or harmful(RR, 1.16; 95% CI, 1.10-1.24)^[4]
• β-carotene likely to be ineffective or harmful(RR, 1.07; 95% CI, 1.02-1.11)^[5]
• Vitamin C unknown effectiveness^[6]
• Vitamin E likely to be ineffective or harmful(RR, 1.04; 95% CI, 1.01-1.07)^[7]
• Selenium unlikely to be benefical(RR, 0.998; 95% CI, 0.997-0.9995) ^[8]

References