Meet The Thyroid-Balancing Nut Wellness Experts Recommend Consuming Daily
If you've been watching some of your favorite wellness experts' Insta-stories, you may have noticed them popping one or two thumb-size nuts daily. The Brazil nut, a tree nut that hails from (you guessed it!) Brazil, is the new food-based supplement du jour. Unlike most nuts, it's not to be casually snacked upon—you wouldn't, for example, want to make a Brazil nut butter or use Brazil nut flour as the base for your gluten-free baked goods. This is because of its superstar component: the incredibly high quantity of selenium. The recommended dietary allowance (RDA) of selenium for adults based on the U.S. Department of Health & Human Services1 is a minimum of 55 micrograms per day. ustone Brazil nut contains around 90 micrograms of selenium, which is already exceeding the daily recommendation! . "As part of my daily supplement regimen, I eat two Brazil nuts every day," says Katie Lemons, the functional medicine expert behind the Twist of Lemons Instagram account and one of the first to popularize the nut as supplement. "They help regulate thyroid function, protect against skin and breast cancer (especially for those with the BRCA1 gene), can prevent mercury toxicity, and are a mood booster. Brazil nuts are safe for all population types without nut allergies. Make sure to buy the nuts in small batches and refrigerate them so they don't go rancid." To further support her daily regimen, this study2 found that 2 Brazil nuts per day were as effective as a supplement for adequately raising selenium levels in the body.
Why is it important to consume selenium?
Selenium is a trace element that is nutritionally essential to humans. Because it is found in our soil, growing conditions will influence concentrations of selenium in plants (and Brazil nuts). Due to this variability of levels in nature and the fact that the body does not absorb 100% of the nutrients in any given food, it is perfectly safe to eat a couple of Brazil nuts a day! Here are a few key reasons why selenium plays such an important role in the body.
Hormone balance (particularly thyroid regulation).
Selenium is the main component of seleno-proteins, which your body needs to make and produce thyroid hormones. If your selenium levels are low, your thyroid has to work harder to make its hormones, which is especially important given the rising rates of thyroid disorders in the western world. Meeting dietary selenium requirements will help to support optimal thyroid health3 and thyroid balance, whether you have a thyroid disorder or are simply trying to help optimize thyroid function. Another study4 showed that selenium supplementation may help improve reproductive outcomes and ease unwanted symptoms experienced by women with PCOS.
Studies have shown selenium's antioxidant function in the body may play a protective role in skin cancer and breast cancer, particularly for people genetically predisposed. "One study5 showed that there were fewer chromosome breaks of the BRCA1 gene," explained Katie, "and basically, if a chromosome breaks it's really bad news and a sign of decay."
Reduced mercury toxicity.
Selenium is an important chelator, meaning that it helps bind to heavy metals—particularly mercury— and excrete them from the body. The goal is to eliminate the mercury before it takes a more permanent place in fatty tissue. By keeping selenium levels adequate, the mineral can regularly help protect against heavy metal accumulation in the body, which is particularly important if you eat a lot of seafood or have silver dental fillings.
Are there other sources of selenium?
There are—selenium is naturally found in many plant and animal foods. Noteworthy options include fish like yellowfin tuna, halibut, sardines, and oysters; pork; cottage cheese; and sunflower seeds. But selenium is far the highest in Brazil nuts, which is why so many experts choose to use the nut as a daily supplement.
Can you OD on selenium?
Absolutely. Symptoms include rashes, dizziness, a metallic taste in your mouth, and more. Stick to one or two Brazil nuts daily, and skip it if you're eating a diet quite high in other selenium-rich foods. Remember that the body is always better able to utilize vitamins and minerals in the presence of whole foods, as opposed to supplements, so a diet containing a variety of selenium-rich, whole foods will best meet your body’s needs.
Liz Moody is an author, blogger and recipe developer living in Brooklyn, New York. She graduated with a creative writing and psychology degree from The University of California, Berkeley. Moody has written two cookbooks: Healthier Together: Recipes for Two—Nourish Your Body, Nourish Your Relationships and Glow Pops: Super-Easy Superfood Recipes to Help You Look and Feel Your Best. She also hosts the Healthier Together Podcast, where she chats with notable chefs, nutritionists, and best-selling authors about their paths to success. Her work has been featured in Vogue, Glamour, Food & Wine & Women’s Health.