We may know not to believe every piece of health advice we hear from celebrities or on the news. But these common health suggestions are so pervasive that most of us don't even think to question them.

1. You should detox.

Detoxification refers to the removal of toxic substances from the body. But the idea that you can remove any toxins from your body by chowing down on kale or subsisting on coconut water is a common misconception. In fact, there's no substance you can eat or drink that will flush out toxins—that's your liver's job, and it gets it done with the help of other organs, such as the kidneys.

2. Vitamin C can prevent colds.

While vitamin C plays a critical role in immune function, there's little evidence to suggest that taking supplements can make colds milder or shorter. In fact, this 29-trial meta-analysis concluded that for the general population, taking vitamin C supplements to prevent colds isn't justified.

3. Eat when you're hungry.

This all too common health advice can be problematic for a few reasons. For one, you probably shouldn't wait until you're starving to eat, as it's easier to make unhealthy choices when hunger has been left for too long.

However, grazing all day long poses problems, too—some sources suggest it can increase your risk of diabetes and other medical conditions. Eating regular meals at around the same time each day is the best option.

4. Hormone therapy isn't safe.

Hormone therapy was once used to treat common symptoms of menopause, such as hot flashes and night sweats. But a large clinical trial exposed health risks such as heart disease and stroke, and doctors quickly stopped prescribing it. However, that doesn't mean it's not safe for certain women. The truth is that it depends on the individual. For healthy women experiencing early-onset menopause, severe hot flashes, and/or lost bone mass, hormone therapy might outweigh the risks.

5. Antidepressants are just a "quick fix."

While it's true that antidepressants can't alleviate the root causes of situational depression, they can help in some important ways. Symptoms of depression can be debilitating. Antidepressants may make it easier for the individual to function on a day-to-day basis, and in time pursue counseling, lifestyle changes, exercise, support groups, and other helpful aids.

6. To lose weight, you need to burn more calories than you consume.

Calories on nutrition labels can be misleading, as foods often have different caloric values once they're in the body. For example, some foods can speed up your metabolism, while others slow it down. When you count calories, you can end up choosing foods that meet your caloric needs but don't actually give you the nutrients you need or leave you feeling satisfied.

7. Spend time outside to get your vitamin D.

Sunshine can indeed boost your vitamin D levels, but unfortunately, the risks outweigh the benefits. The sun's rays contain ultraviolet (UV) light, a carcinogen that can increase your risk of skin cancer. Make sure to apply sunscreen whenever you go outside, and address a vitamin D deficiency by seeing your doctor to see if you should take supplements.

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