Many things we do to heal ourselves and stay healthy are based not on modern science but on outdated ­theories and unproven practices. ­Bottom Line ­Personal asked Dr. Paul Offit to tell us the truth about four supposedly “healthy” remedies…

Belief: Treat a sprain with R.I.C.E. (Rest, Ice, Compression, Elevation).

Truth: Treating a sprain with R.I.C.E. can delay healing.

When an ankle is sprained, the damaged ligaments surrounding it release substances that promote inflammation, which triggers the body to boost blood flow to the injured area. Increased blood flow steers clotting factors and immune cells to the injury, where they help stop internal bleeding and remove damaged cells. Inflammation also promotes production of the protein collagen, which is needed for recovery. In other words, inflammation fuels healing.

But inflammation also causes pain. That’s why the R.I.C.E. protocol, ­created by sports medicine physician Gabe Mirkin in 1978, gained traction, and many medical groups, including the American Academy of Orthopaedic Surgeons and National Athletic Trainers’ Association, have endorsed it for treating sprains and other minor injuries. Rest, ice, compression (wrapping) and elevation all feel good in the moment, but ice and compression decrease blood flow to the injured area—the opposite of what is needed for healing. ­Result: A prolonged period of healing and, possibly, improperly healed ligaments.

Important finding: There is “limited evidence supporting the efficacy” of the R.I.C.E approach, concluded a 2020 study in World Journal of Orthopedics. And in 2015, Dr. Mirkin himself renounced his own popular advice.

What to do instead: Try to tough out the pain without ice and compression. After the initial swelling has decreased, applying warmth to the area—a heating pad or a warm, damp cloth—for an hour may provide some relief. Elevation also may help. Also: After a few days of rest and once the swelling has gone down, try gentle ankle movements to increase blood flow to the area. Example: Draw an imaginary alphabet with your foot.

Belief: Reducing your fever helps you get better faster.

Truth: Treating a fever can prolong or even worsen an infection.

Say you’ve caught a bug and feel awful—fever, shivering, head and body aches. Your first goal may be to relieve your symptoms by popping aspirin, ­acetaminophen (Tylenol) or ibuprofen (Motrin, Advil). These medicines may reduce your fever and help you feel better in the short term, but they don’t fight the pathogen that is making you sick. In fact, they may prolong the infection.

Here’s why: When viruses, bacteria, parasites or other pathogens enter the bloodstream, the immune system releases proteins called cytokines that travel to the brain, where they enter the hypothalamus, the area that regulates body temperature. There, the cytokines set off a chain of events to reset the body’s thermostat to a higher temperature, usually over 100°F, because the immune system is enhanced at higher temperatures. At this elevated temperature, the search-and-destroy immune cells neutrophils seek out and kill the foreign invaders.

Fever reducers, on the other hand, tell the brain to reduce your temperature. As your temperature drops, the neutrophils take a break, allowing viruses and bacteria to flourish. Result: Mild infections may last longer, and severe infections can worsen or even become fatal.

Surprising: There are 5% more ­cases of influenza (and 5% more influenza-­related deaths) per year in societies where fever reducers are frequently used.

What to do instead: The truth is, we’re not supposed to feel good when we are sick. If possible, stick it out…stay in bed…hydrate…and let your body fight the infection the best way it knows how—by raising your temperature.

Caution: A high fever induced by infection is rarely dangerous—but in an older person, a high fever that lasts longer than two or three days can put stress on the heart, and fevers induced environmentally, such as those that occur in football players or outdoor laborers wearing heavy clothing, can cause heat stroke.

Belief: Antioxidant supplements such as A, C and E help prevent disease.

Truth: Supplements are overkill.

The process of converting food into energy creates free radicals, potentially damaging by-products that, unchecked, may cause cancer and cardiovascular disease (CVD). Free radicals also enter the body through cigarette smoke, heavy metals found in certain foods and other environmental toxins.

Our bodies produce antioxidants, compounds that fight free radicals, but not enough antioxidants to counteract all the free radicals, so Mother ­Nature provided us with antioxidant-rich fruits, vegetables and other foods rich in vitamins A, C, E, lycopene and beta-­carotene. This is one reason people who consistently eat more produce live longer and have lower rates of cancer and other age-related diseases.

Problem: Many people think, If ­antioxidants in foods prevent disease, then antioxidant supplements will help even more. In fact, by 2012, more than half the US population was taking supplements, according to a National Health and Nutrition Examination Survey.

But this approach doesn’t work when it comes to neutralizing free radicals…and it often backfires. Studies have failed to show that antioxidant supplementation reduces risk for cancer and heart disease. The US Preventive ­Services Task Force states, “Limited evidence supports any benefit from ­vitamin and mineral supplementation for the prevention of cancer or CVD.”

As it turns out, antioxidants in foods come packaged with thousands of other plant-based chemicals that exert their own beneficial effects on health. Manufactured vitamins do not.

Surprising: Supplementing with the antioxidants vitamin A and beta-carotene dramatically increases risk for lung cancer, prostate cancer and heart disease, while vitamin E supplementation increases the risk of dying from any cause. Possible reason: Excessive quantities of individual antioxidants hinder the body’s natural ability to kill foreign cells, such as bacteria and cancer cells, and clean out clogged arteries.

Belief: Sunblock protects skin.

Truth: “Sunblock” is a misnomer.

The FDA no longer allows products to be called “sunblock” because it implies that they “block” the sun. Besides staying indoors and wearing sun-protective clothing such as broad-brimmed hats and long-sleeved shirts when outside, there’s no way to entirely block the sun from damaging your skin.

The appropriate term is “sunscreen”—these products help reduce the amount of damaging UV rays absorbed by skin. To convey the degree to which they prevent sunburn, sunscreens are labeled with numbers—products with a sun protection factor (SPF) of 15 screen out 93% of UVB rays…an SPF of 30 screens out 97%…and an SPF of 50, 98%. No sunscreens, not even ones with an SPF of 100, screen out 100% of UV rays.

These numbers are reliable measures of sun protection only if the sunscreen is used as it’s designed to be used—at least one full ounce (enough to fill a shot glass) to cover all exposed skin on the face and body, applied 15 minutes before heading outside and reapplied every two hours and again immediately after swimming or perspiring, per the American Academy of Dermatology. Reality: Most people apply less than half the recommended amount. Added problem: Sunscreen gives people a false sense of protection, prompting them to stay out in the sun longer.

What to do: Cover as much of your skin as possible with sun-protective clothing. Regular clothing works, too, but it must be opaque—a sheer linen top won’t block much, but a tightly woven long-sleeved denim shirt will. For any exposed skin, including often-overlooked places such as eyelids, tops of ears and the scalp, use ample sunscreen and reapply religiously.