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All About Antioxidants: Ask the Nutritionist

WebMD Chief Medical Editor, Michael Smith, MD, answers your questions about antioxidants and nutrition.

Question:
What are free radicals? What kind of damage can they do to your body?
Answer:

"Free radicals" are unstable atoms, or molecules, in your body. They are missing important components that would make them more stable. So they rob other cells of those components to meet their needs. This causes injury to previously healthy cells. Over time, this damage can lead to diseases such as cancer, heart disease, or Alzheimer’s disease.

Your body produces free radicals through its normal processes. Your body also contains antioxidant molecules, which deactivate harmful free radicals. But things like cigarette smoking, pollution, and excessive alcohol consumption can create so many free radicals that your body has a hard time defusing them on its own.

Question:
In terms of antioxidants, what makes something a "super food"?
Answer:

The term "super food" is not an official designation. It's commonly used to describe foods that may help prevent or even treat certain medical conditions. Any food that is packed with healthy nutrients can be considered a super food. Examples include blueberries with healthy antioxidants, salmon that contains omega-3 fatty acids, beans that provide you fiber, and milk as one of the best sources of calcium.

Question:
I am a 30-year-old woman. Right now, I take 400mg daily of vitamin E for my skin. Is this dosage too high for a woman my age?
Answer:

The upper limit for vitamin E in an adult is 1000 mg a day. This means more than that could increase the chance of side effects. You’re well under that amount.

Question:
Could taking a 750 mg tablet of L-Carnitine every day have any negative effects on my health?
Answer:

Medical studies on L-Carnitine have used doses higher than that on their subjects, so you should be just fine. However, side effects are always possible. These include nausea, vomiting, stomach cramps, heartburn, and diarrhea.

Question:
What is the best type of calcium supplement for women to take?
Answer:

There are two main types of calcium in supplements. Both work just fine. You may hear that calcium carbonate has more “elemental calcium” than calcium citrate. But all you need to pay attention to is the amount of calcium on the supplement's label.

You should take calcium carbonate with food. You can take calcium citrate with or without food. If you have constipation from calcium supplements, opting for calcium citrate may help, as it’s less likely to cause stomach problems.

Don’t take more than 500 mg of calcium at one time because your body can’t effectively absorb more than that. For example, if your doctor told you to take 1000 mg a day, take 500 mg in the morning and 500 mg at night.

Question:
Is there a correlation between taking multivitamins and experiencing an improvement in your sense of smell and taste?
Answer:

Multivitamins have many nutritional benefits. But there is no medical evidence to suggest that taking them can help improve your sense of smell or taste.

Question:
What are OPC antioxidants? How are they beneficial to my health?
Answer:

OPCs, short for "oligomeric proanthocyanidins", are in the flavonoid class. Flavonoids are antioxidants found naturally in plants. They help make blueberries blue, cherries red, and blackberries black.

Some studies show that OPCs can help keep your heart healthy. If you see a black food, it’s likely to be a good source of OPCs; black sesame seeds, black beans, black rice, or black quinoa for example. (Not all black foods have OPCs, like black pasta that gets its color from squid ink.) Grape seed extract, often sold in supplement form, is also rich in OPCs.

Question:
Can genistein supplements really help relieve my hot flashes and other menopause symptoms?
Answer:

Possibly. Some research suggests that genistein may help relieve hot flashes and other menopause symptoms, such as mood changes and anxiety. Other studies found no benefit. Genistein can interact with certain medicines, so check with your doctor or pharmacist before trying it.

Question:
Is it necessary to focus on consuming antioxidants when my body already makes them? If so, why?
Answer:

Absolutely! Antioxidants help neutralize free radicals in your body that can damage your cells and lead to disease. Your body creates its own antioxidants. But most people are exposed to elements in the environment that increase free radical production. This is why maintaining a diet rich in antioxidants is beneficial. Plus, foods that are rich in antioxidants -- fruits and vegetables -- have many other health benefits.

Question:
I'm a 52-year-old man. How much red wine should I drink a day to benefit from the antioxidants it contains?
Answer:

I don't recommend drinking red wine for the purpose of getting antioxidants. There are other ways to pack your diet with antioxidants, like with fruit and vegetables. However, red wine can be part of your antioxidant plan. As a man, you should limit your wine intake to no more than two 5 oz. glasses a day. Drinking more than that could offset any health benefits and actually increase your risk for certain diseases.

Red wine has been linked to a lower risk of heart disease and some cancers. It is rich in an antioxidant called resveratrol, which is also found in red grapes, grape juice, peanuts, and mulberries.

Question:
What's the best way to cook vegetables so that they retain the healthy vitamins I need?
Answer:

Steaming your vegetables is the best way to preserve the nutrients in them. Limiting the amount of time you cook them also helps. This is true for boiling as well, since more nutrients can leach out into the water. It's nice to know that with soups and stews, this doesn’t matter. You’ll consume the nutrients in whatever broth or liquid you've cook those veggies in.

Question:
Are gummy vitamins as healthy as other kinds of vitamins?
Answer:

Gummy vitamins are just as nutritious as regular vitamins. The amount of vitamins and minerals listed on the label is more important than the form they actually come in.

Even though gummy vitamins may be tasty, don't take more than recommended. You can take too many vitamins. Also, gummy vitamins often stick to your teeth. So if your gummies are not sugar free, this could cause tooth decay and enamel erosion.

Question:
I am 32 years old and going through menopause. I also have osteoporosis. What kinds of vitamins should I be taking?
Answer:

Make sure you’re getting plenty of calcium and vitamin D. These nutrients are critical for maintaining strong bones, especially since you’re apparently going through menopause at a young age.

Aim for 1000 mg of calcium a day. The best sources are dairy, such as low-fat or fat-free milk and yogurt. Soy milk and almond milk are also great sources. If you don't think you’re getting enough calcium, add a calcium supplement to your daily routine.

Vitamin D can be tough to get from your diet, but it is critical for calcium absorption. You need 600 IUs of vitamin D a day. The best sources are fatty fish, such as salmon and tuna. Milk and orange juice are often fortified with vitamin D. If you don’t think you’re getting enough, include a supplement. You can often find calcium and vitamin D combined in one supplement.

Question:
I accidentally doubled up on my multivitamin and prenatal vitamins. Now I'm not feeling well. Should I be concerned?
Answer:

Taking too many vitamins at once can sometimes cause an upset stomach. But doubling up on your vitamins for just one day won’t be a problem. Your body will quickly get rid of the excess. Some vitamins can build up in the body, but that won't happen from taking double the amount on just one occasion.

Question:
Should I jump into a strictly vegan diet from the typical American diet, or should I transition gradually? Will my body know how to adapt immediately?
Answer:

Your body will adjust. There are no risks with becoming vegan overnight.

It can be tougher to get certain nutrients when you are vegan, such as protein, iron, and calcium. Also, make sure to get plenty of vitamin B12, since that generally comes from animal products. Some soy-based beverages, breakfast cereals, and veggie “meats” are often fortified with B12.

Thank you for joining us for WebMD Ask the Nutritionist. Be sure to check in on Wednesday, Nov. 14th, at 1 p.m. ET, when the discussion topic will be "Eating a Healthy Breakfast." Sign up if you'd like an email reminder the day before the event.

WebMD Ask the Specialist Transcript

Reviewed by Michael W. Smith, MD on October 08, 2012

The opinions expressed in this section are of the Specialist and the Specialist alone. They do not reflect the opinions of WebMD and they have not been reviewed by a WebMD physician or any member of the WebMD editorial staff for accuracy, balance or objectivity. WebMD is not a substitute for professional medical advice, diagnosis, or treatment. Never delay or disregard seeking professional medical advice from your doctor or other qualified health provider because of something you have read on WebMD. 

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