Are Brazil nuts a good way to get enough selenium?
Yes, Brazil nuts are very high in selenium. But they contain so much selenium that it can be unsafe to eat too many of them.
Like other vitamins and minerals, selenium has a recommended intake and a safe upper limit. Adults should get at least 55 to 70 micrograms (mcg) of selenium, but not more than 400 mcg a day.
One Brazil nut has about 70 to 90 mcg of selenium. So eating one or two Brazil nuts a day is a great way to get enough selenium. But if you eat more than a small handful of Brazil nuts, you could easily go over the upper limit.
Getting too much selenium on a regular basis can cause several problems including an upset stomach, garlic breath odor, hair loss, white blotchy nails, and mild nerve damage. Have more questions? See our fact sheet on selenium.
I know that carrots are healthy and have lots of vitamin A. But I’ve also heard that too much vitamin A can be dangerous, so do I need to limit how many carrots I eat?
Vitamin A can be toxic at high doses, causing liver damage and birth defects if a woman is pregnant. However, this applies only to the form of vitamin A—called preformed vitamin A or retinol—that is found in foods from animals, such as beef liver, milk, milk products, and some dietary supplements.
Plant foods, such as carrots, spinach, and red peppers, contain a form of vitamin A called beta-carotene. Consuming high amounts of beta-carotene can turn the skin yellow-orange, but this condition is harmless. Beta-carotene does not cause birth defects or the other more serious effects caused by getting too much preformed vitamin A.
So enjoy plenty of carrots and other fruits and vegetables without worrying about getting too much vitamin A. Have more questions? See our fact sheet on vitamin A.
Is valerian a “natural” form of Valium®? And if so, how much should I take?
Although their names are similar, valerian and Valium® are not related to each other. Valium® is a medication available only by prescription. It is the brand name for the drug diazepam which is used to treat anxiety, panic attacks, and other conditions.
Valerian is an herb that is sold as a dietary supplement. It is found in some products promoted as mild sedatives and sleep aids, although it is not clear to what extent valerian is helpful for these conditions. Valerian, like all dietary supplements, should not be taken in place of, or in combination with, prescribed medications without your health care provider’s approval.
Like many herbs, scientists are not certain which components of valerian are responsible for its effects. Dietary supplements are not required to be standardized in the United States, so formulations of valerian products may vary. It can be difficult to compare one valerian product with another and determine appropriate doses. We recommend talking with your health care provider for advice. Have more questions? See our fact sheet on valerian.