Vitamin E, C, and β-carotene are antioxidants that have been studied for their potential role to lower the risk of type 2 diabetes.
These vitamins are known for their antioxidant properties, which may help protect against the development of type 2 diabetes by reducing oxidative stress. However, the evidence from studies on their impact on diabetes risk is mixed, and more research is needed to draw definitive conclusions.
A study conducted as part of the Women’s Antioxidant Cardiovascular Study (WACS) aimed to investigate the long-term effects of supplementation with vitamin C, vitamin E, and β-carotene for primary prevention of type 2 diabetes. The study involved 8171 female health professionals aged 40 years and older, with either a history of cardiovascular disease (CVD) or ≥3 CVD risk factors. Participants were randomly assigned to receive vitamin C (ascorbic acid, 500 mg daily), vitamin E (RRR-α-tocopherol acetate, 600 IU every other day), β-carotene (50 mg every other day), or placebos. The study found a trend toward a modest reduction in diabetes risk in women assigned to receive vitamin C compared to those assigned to receive placebo (relative risk (RR): 0.89; 95% CI: 0.78, 1.02; P = 0.09). However, a trend for a slight elevation in diabetes risk was observed for vitamin E treatment (RR: 1.13; 95% CI: 0.99, 1.29; P = 0.07). No significant effect was observed for β-carotene treatment (RR: 0.97; 95% CI: 0.85, 1.11; P = 0.68).
The study concluded that there were no significant overall effects of vitamin C, vitamin E, and β-carotene on the risk of developing type 2 diabetes in women at high risk of CVD. Although sensitivity analyses suggested a modest protective effect of vitamin C, this result could be a chance finding and needs to be confirmed in future investigations. The study does not support recommending antioxidant supplements for the primary prevention of type 2 diabetes.
Other research has shown varying results. Some prospective cohort studies have found that vitamin C intake was significantly lower among incident cases of type 2 diabetes, and serum α-tocopherol levels were associated with a lower risk of type 1 or type 2 diabetes. However, serum β-carotene and α-tocopherol concentrations were nonsignificantly associated with a reduced risk in a cohort of Finns. In some case-control and cross-sectional studies, significantly lower serum levels of α-tocopherol, carotene, or vitamin C have been observed in individuals with diabetes than in control subjects. Some prospective studies have shown that higher vegetable and fruit consumption may lower the risk of developing diabetes, suggesting that antioxidants in the diet may have a synergistic effect.
What Are The Dietary Sources Of Vitamin E, C, and β-Carotene?
Vitamin E, C, and β-carotene are essential nutrients that can be obtained from various dietary sources.
Vitamin E is a fat-soluble antioxidant that can be found in vegetable oils, nuts, seeds, and whole grains. The main dietary sources of vitamin E are vegetable oils, such as sunflower, safflower, and soybean oil, which provide about 40% of the total vitamin E intake. Nuts and seeds, such as almonds, peanuts, and sunflower seeds, are also significant sources of vitamin E, contributing about 8% of the total intake. Other sources of vitamin E include fortified cereals, green leafy vegetables, and fish.
Vitamin C is a water-soluble antioxidant that is widely distributed in fruits and vegetables. The main dietary sources of vitamin C are citrus fruits, such as oranges and grapefruits, which provide about 40% of the total vitamin C intake. Non-citrus fruits, such as strawberries, kiwi, and papaya, are also important sources of vitamin C, contributing about 10% of the total intake. Vegetables, such as bell peppers, broccoli, and spinach, are also rich in vitamin C and provide about 20% of the total intake.
β-carotene is a provitamin A carotenoid that can be converted into vitamin A in the body. The main dietary sources of β-carotene are yellow, orange, and green leafy fruits and vegetables, such as carrots, spinach, lettuce, tomatoes, sweet potatoes, broccoli, cantaloupe, and winter squash. In general, the more intense the color of the fruit or vegetable, the more β-carotene it has.
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Symptoms of type 2 diabetes
Type 2 diabetes is a chronic condition that affects the body's ability to regulate and use sugar (glucose) properly. The pancreas does not produce enough insulin, a hormone that regulates the movement of sugar into the cells, and cells respond poorly to insulin, leading to high blood sugar levels.
Symptoms of type 2 diabetes can develop slowly over time and may include:
1. Increased thirst (polydipsia)
2. Frequent urination (polyuria)
3. Feeling hungrier than usual (polyphagia)
4. Unintended weight loss
5. Fatigue
6. Blurred vision
7. Slow-healing sores
8. Frequent infections
9. Numbness or tingling in the hands or feet
10. Areas of darkened skin, usually in the armpits and neck.
If you notice any symptoms of type 2 diabetes, it is essential to see your healthcare provider for a diagnosis. Simple blood tests can diagnose type 2 diabetes, and early detection and treatment can improve your quality of life and reduce the risk of severe complications.
