6 chemicals in food, makeup, and skin-care products that aren't as dangerous as you think

Another rat study prompted a similar association between saccharin, a zero-calorie sweetener sold under the brand name Sweet'N Low, and cancer. In the 1980s, products with saccharin were required to carry a warning label saying that the sweetener was "determined to cause cancer in laboratory animals."

The study was later debunked after scientists discovered that the rats were prone to bladder cancer to begin with. Dozens of other studies have also found no association between saccharin and cancer. In 2016, the National Toxicology Program removed saccharin from its list of cancer-causing ingredients.

In the late 1990s, a viral email suggested that the aluminum in antiperspirants might be giving people breast cancer. The claim was backed up by preliminary research, but has since been proven false.

Both the European Commission's Scientific Committee on Consumer Safety and the American Cancer Society find no clear link between breast cancer and aluminum-containing antiperspirants. Evidence suggests that our bodies only absorb small amounts of aluminum from antiperspirants — not enough to be considered dangerous.

Read more: Toxic chemicals in your home could be linked to cancer, autism, and reproductive issues. Here are 4 of the most concerning.

In 2004, a small study linked parabens — preservatives found in make-up and skin-care products — to breast cancer, but its methodology was flawed. The study looked for evidence of parabens in existing breast cancer tissue, but didn't identify where they came from or whether they caused or contributed to cancer.

There's also been some concern that parabens may disrupt hormone systems in a manner similar to estrogen, but the most common parabens are far weaker than the body's natural estrogen.

The FDA hasn't found any concrete evidence that parabens in cosmetics have an effect on human health. In fact, the chemicals help to prevent harmful bacteria from forming in your make-up, lotion, or sunscreen.

Read more: Cancer-causing toxins were just found in foundation and sparkly makeup — here are 11 chemicals that could lurk in your lipstick, lotion, and eye powder

In 1968, a biomedical researcher claimed to experience numbness and heart palpitations after eating at Chinese restaurants. The cause of his symptoms, he said, was a food additive called MSG, or monosodium glutamate, which is also found in processed meats, chips, and canned vegetables.

In the 1990s, the FDA commissioned a review of the additive and found that MSG was safe to consume. The review also found that people who experienced headache, numbness, or drowsiness were likely to have eaten large amounts of MSG on an empty stomach.

But the stigma surrounding MSG has carried on: Around 42% of Americans still try to avoid consuming the ingredient.

Conscious consumers might be inclined to purchased shampoo or body wash labeled "sulfate-free," but there's little reason to fear the sulfates. The ingredients are a surfactant — essentially a heavy-duty soap that makes it easier to trap oil and grease.

In the 1990s, sulfates were thought to be carcinogenic — a theory that isn't supported by scientific evidence. The only people who should be concerned for now are those with existing sensitivities, since sulfates can be both drying and irritating to the skin.