Scientists Just Discovered a Concerning Health Risk of Taking Biotin
Key Points
If you’re experiencing hair loss or have brittle nails, you might be considering supplementing with biotin—or maybe you already are. And for good reason. Biotin or vitamin B7, is essential for energy metabolism. Along with vitamin A, biotin helps stimulate the production of keratin, a conglomeration of proteins that helps improve the health and strength of nails and hair.1 And if you’re of a certain age, you know how this tends to decrease through the years.
But age isn’t the only contributing factor. Nutritional deficiencies can contribute to weaker hair and nails, as can certain cancer treatments. Because biotin supplements are so common these days, you might assume that they’re safe for everyone. But recent research suggests you might want to rethink supplementing with biotin.2 Here’s why.
How Was This Study Conducted?
Researchers from the University of Lausanne, in Lausanne, Switzerland, performed this study in their lab, so it was not directly performed on humans, but it did use human (and rodent) cells. Scientists already know that cancer cells use glutamine, a nonessential amino acid, for energy. (Nonessential means that your body can produce it and does not need to get it from food.) When cancer cells are “fed” glutamine, they multiply and grow more easily. As the researchers explain, cancer cells thrive on glutamine so much that they can become “addicted” to it.
But cancer cells are sneaky. They want to proliferate, so when their preferred source of energy is deficient, they’ll find another metabolic pathway to get what they need—referred to as metabolic flexibility. Researchers wanted to see how cancer cells reacted and adapted when glutamine was scarce (such as in cases of malnutrition or infection). They tested this on about a dozen different cancer types.
What Did This Study Show?
Researchers knew that cancer cells have backup pathways to get what they need to proliferate when glutamine is unavailable. In this case, they discovered a pathway that used the compound pyruvate as an energy source in the absence of glutamine. Pyruvate is a byproduct of glycolysis, the process of glucose being broken down to use for energy. This pyruvate backup system depends on pyruvate carboxylase, a mitochondrial enzyme, which, in turn, requires biotin to function.
What this finding means is that biotin availability determines whether pyruvate can compensate for the lack of glutamine. When biotin is not available, pyruvate carboxylase is not able to function, and cancer cells have a harder time proliferating in the absence of glutamine.
Researchers also examined the relationship with FBXW7, a tumor suppressor gene that is commonly mutated in several types of cancer. They found that mutations in FBXW7 reduced levels of pyruvate carboxylase—essentially blocking the cancer cells’ ability to use the pyruvate pathway for energy.
Limitations of this study include that it was done in the lab and not in actual humans, though these results add to the mounting evidence of alternative pathways for cancer cell proliferation. There is also a chance that other cells may have interfered with the results, and that there could have been errors in the laboratory processes.
How Does This Apply to Real Life?
Biotin is a necessary nutrient found in foods you probably eat regularly—like eggs, salmon, pork, beef, sunflower seeds, sweet potatoes and almonds. Your body needs biotin, and getting it from a variety of foods is great. But based on this study, you may want to consult a health care provider before you start taking a biotin supplement, especially if you’ve previously had cancer or are currently undergoing treatment.
As for those who have not had cancer, biotin still comes with certain effects that oncologists are concerned about. A short review found evidence from several studies suggesting that biotin has the potential to interfere with laboratory test results for thyroid, breast, endometrial, ovarian, germ cell, paraneoplastic and prostate cancers. This may potentially delay or alter patients’ treatment plans.
In addition, there is little evidence to suggest that supplementing with biotin helps with common hair loss and nail disorders, though it may be helpful for those who are experiencing these conditions due to a vitamin B7 deficiency.
If you’re dealing with hair loss or brittle nails, consider consulting with a health care provider to have bloodwork to test your vitamin B7 levels. If they’re normal, you could discuss using other treatments for these issues, like minoxidil (aka Rogaine). This extends to those going through cancer treatment. In one randomized controlled trial, 88% of patients using topical minoxidil experienced significant improvement of hair regrowth after chemotherapy compared with 55% in the placebo group.
Besides avoiding supplementing with biotin, you may also want to examine your intake of added sugar, since pyruvate and glucose (sugar) are tightly linked in metabolic pathways (like the aforementioned glycolysis). And we know that excessive sugar intake is linked with an increase in inflammation, which is also associated with cancer.4 While the American Cancer Society doesn’t provide its own specific recommendations when it comes to sugar intake (other than limiting or avoiding sugar-sweetened beverages), the American Heart Association recommends that no more than 6% of your calories come from added sugar.56 If you eat about 2,000 calories per day, that's about 30 grams of added sugar per day.
Our Expert Take
This study suggests that when glutamine is lacking, cancer cells may use an alternative energy pathway that is biotin-dependent. In addition, research suggests that supplementing with biotin may interfere with several types of cancer test results, which could affect diagnoses and treatment plans. If you have cancer, have a history of cancer or have a family history of cancer, speak with a health care provider before supplementing with biotin. Instead, try to get your biotin through foods like eggs, salmon and sweet potatoes.
While there are some nutrients that you may benefit from supplementing, like vitamin D, there are some that may not be worth your money—or the potential complications. Biotin is found in a variety of sources, including animal- and plant-based foods. Focusing on whole foods and limiting highly processed ones will help ensure you get enough of this important nutrient without going overboard on it.