The Best Foods to Eat Together for Nutrient Absorption
When it comes to nutrition, it's easy to think of nutrients traveling through your body like little commuters, beelining their way to cells and tissues. And while it certainly makes for a fun visual, it's definitely not that simple. Case in point: Some nutrients aren't optimally absorbed if you eat them on their own. Instead, they need to be paired with other nutrients in order for your body to get the most out of them — and that's as easy as eating certain food combos together.
Doing so allows said nutrients to interact and trigger the chemical reactions needed to support maximum absorption, says Alice Figueroa, M.P.H., R.D.N., founder of Alice in Foodieland. By contrast, if you eat these nutrients separately, one might already be digested and broken down by the time you eat the other, ultimately reducing the chances of the two interacting and you being able to reap the potential benefits.
But wait — how do you know you're eating enough of each nutrient to ensure top-notch absorption? Simply combining nutrients in a balanced, colorful meal will get the job done, according to Figueroa. "The most approachable and realistic way to practice food pairing is by eating a diverse plate that includes colorful fruits and vegetables, healthy fats, and protein," she says. "If you have colorful, diverse meals and snacks, you are likely to be getting all the nutrients you need from food without needing to worry about measuring portions or servings."
Ahead, learn about eight essential nutrient pairings, along with suggested food combos from dietitians so you can easily incorporate each nutrient duo into your diet.
Catechins + Vitamin C
If you're a tea super-fan, you've likely heard of catechins, aka the compounds in tea that make the drink so darn good for you. Catechins are antioxidants, meaning they combat oxidative stress by neutralizing free radicals. (Excess oxidative stress, BTW, can lead to chronic conditions including heart disease, rheumatoid arthritis, and cancer.) There's a catch, though: On their own, catechins are unstable in neutral or non-acidic environments such as our intestines, says Michelle Nguyen, R.D., a registered dietitian at Keck Medicine of the University of Southern California. In there all alone, catechins are prone to breaking down, leading to poor absorption overall.
Enter vitamin C, an essential nutrient involved in immune function and collagen synthesis. Vitamin C acidifies the intestinal environment, which prevents catechins from degrading, according to Kylie Ivanir, M.S., R.D., registered dietitian and founder of Within Nutrition. This optimizes their absorption in the intestines, ensuring your body can actually make use of that antioxidant goodness. (Related: The Most Antioxidant-Rich Foods to Stock Up On, Stat)
Food Pairings: vitamin C-rich fruits with tea or a tea-based smoothie
The classic combo of lemon juice plus tea is a perfect example. "You can also look for ready-made tea options that have [added vitamin C], but adding a squeeze of [fresh lemon juice] is best," says Ivanir. Not crazy about hot tea? Make a matcha green tea smoothie with strawberries or a vitamin C-packed fruit of your choice, suggests Nguyen.
Vitamin C + Plant-Based Iron
Vitamin C also enhances absorption of non-heme iron, a type of iron found in plant foods such as beans, lentils, nuts, seeds, tofu, and spinach. Iron is needed for making hormones and carrying oxygen in the blood. However, due to its chemical structure, non-heme iron has a low bioavailability, meaning it's not easily absorbed by the intestines. (FYI, the other type of iron is heme iron, which is found in animal products such as poultry, beef, seafood, and shellfish, is more easily absorbed on its own, says Figueroa.)
Pairing non-heme iron with vitamin C can boost the former's absorption, as vitamin C forms a soluble (aka dissolvable) bond with non-heme iron, according to an article published in the Journal of Nutrition and Metabolism. And this changes the chemical structure of non-heme iron into a form that's more easily absorbed by intestinal cells, notes Figueroa.
Food Pairings: a squeeze of lemon juice into lentil soup; bell pepper sticks with hummus; extra tomatoes and bell peppers mixed into black bean chili. (Related: How to Cook with Citrus for a Vitamin C Boost)
Calcium + Vitamin D
It's no secret that calcium is crucial for bone health, but simply consuming calcium isn't enough; you'll need to fuel up on vitamin D, too. "Vitamin D is needed to optimize calcium absorption," says Figueroa. It works by transporting calcium through intestinal cells, according to a scientific review in the World Journal of Gastroenterology. In fact, without enough vitamin D, you'll only be able to absorb 10 to 15 percent of the calcium you eat, notes Figueroa. (Related: The Low Vitamin D Symptoms Everyone Should Know About)
It's worth noting that you don't necessarily need to eat vitamin D and calcium at the same exact time to optimize absorption, says Figueroa. This is because vitamin D is fat-soluble, meaning it's stored in your fatty tissue for a long time, she explains. As a result, your body always has some vitamin D available. That said, "it's more important to focus overall intake of [foods rich in calcium and vitamin D] throughout the day," rather than at the same time, she notes. Think of it as a wider "time frame" for pairing these nutrients. But if you're all about efficiency (or just forgetful), it may help to eat 'em together. (Related: The Fit Woman's Guide to Getting Enough Calcium)
Food Pairings: calcium-rich cruciferous greens (such as broccoli or turnip greens) with vitamin D-rich fish (such as salmon and tuna); mushroom stir-fry with calcium-fortified tofu. Speaking of which...
Since this combo is so important for bone health, it's common to find calcium-rich foods (such as dairy milk and yogurt) fortified with vitamin D. Some products — i.e. plant-based milks — are often fortified with both nutrients, which may help in terms of efficiency and convenience, explains Figueroa. (The exception is homemade nut milks, which aren't good sources of calcium, notes Figueroa. If you want both nutrients in one product, store-bought fortified versions are the best choice.)
Vitamin D + Magnesium
Vitamin D also increases intestinal absorption of magnesium, a mineral involved in functions such as cell repair and heart rate, explains Ivanir. And as it turns out, the feeling is mutual: Magnesium is a cofactor for vitamin D synthesis, she says. This means magnesium needs to be present in order for the skin to make vitamin D; it's the perfect example of a two-way street.
Food Pairings: salmon or trout — which bring the vitamin D — coated with almonds instead of breadcrumbs for that dose of magnesium; salad topped with salmon and pumpkin seeds; mushroom stir-fry topped with chopped cashews. (Related: The Benefits of Magnesium and How to Get More of It In Your Diet)
Carbohydrates + Protein
Sometimes improving absorption is all about slowing things down. Such is the case of carbs and protein, an important combo for satiety, energy, and post-workout recovery. "When [you] eat carbohydrates, including vegetables and fruits, they get broken down into glucose," the body's main source of energy, explains Figueroa. This increases your blood sugar levels, which is a natural and normal response. The problem is when your blood sugar increases too fast, causing a blood sugar spike. Over time, this can lead to insulin resistance and high blood glucose levels, boosting your risk of prediabetes and diabetes, she says.
Proteins break down at a slower rate than carbohydrates. So, eating the nutrients at the same time allows carbs to break down more slowly, "helping stabilize blood sugar levels because the carbs [release] less sugar into the bloodstream at once," says Ivanir. This is crucial not only for sustaining satiety and energy on a daily basis but for recovering after exercise, too. Chowing down on some carbs post-workout helps with muscle recovery by kickstarting the process of replenishing your body's carbohydrate stores (your body's first source of fuel).(Related: What to Eat Before and After a Morning Workout)
Food Pairings: oatmeal with a side of eggs; oatmeal with protein powder; apple slices or whole-wheat toast with nut butter. (Or any of these post-workout snacks trainers and dietitians swear by.)
Curcumin + Piperine
The main compound in turmeric, curcumin has stellar antioxidant and anti-inflammatory properties, according to a scientific review in the journal Foods. But like the catechins in tea, curcumin "is poorly absorbed when ingested on its own," says Ivanir. The reason? It's quickly metabolized and eliminated by the body, so it can be difficult to soak up all its benefits.
The solution: Add black pepper to the mix. Its main compound — piperine — can actually increase the bioavailability of curcumin by about 2000 percent (!!), according to Ivanir. Piperine helps curcumin pass through the intestinal lining and into the bloodstream, thus improving absorption, she says. "Piperine may also slow down the breakdown of curcumin by the liver," she adds, helping to counteract the speedy elimination of curcumin, ultimately giving your body more time to absorb the compound.
Food Pairings: a sprinkle of black pepper and turmeric on roasted veggies with olive oil, in scrambled eggs, in soups, or in rice; a dash of black pepper to your turmeric latte or golden milk protein shake.
Zinc + Animal Protein
Although the body needs very small amounts of zinc, this mineral supports many physiological processes such as immune function, says Rachel Werkheiser, M.S., R.D., project management dietitian at Sodexo. The best sources of zinc are animal products, such as poultry and fish; the zinc in these foods is most easily absorbed by the body. Plant foods such as whole grains, legumes, and seeds also offer zinc, says Werkheiser. However, they also contain phytates, aka "antinutrient" compounds that actually bind to zinc and reduce its absorption, according to Harvard. T.H. Chan School of Public Health. (Related: 5 Minerals That Seriously Supercharge Your Workouts)
To improve zinc absorption from whole grains/legumes/seeds, pair them with animal protein, which binds with phytate, preventing it from linking up with zinc and, thus, allowing optimal absorption, according to a review published in Nutrients. (Animal food not your thing? Soaking whole grains and legumes in water for eight to 12 hours before cooking also helps reduce their phytate content, says Ivanir.) However, it's worth noting that zinc from other plant sources — such as mushrooms or kale — is also best absorbed with an animal protein source, as it "is able to increase the absorption of zinc" in general, which is thought to work by increasing its solubility in the intestines.
Pair all zinc-rich plant foods — especially phytate-containing whole grains, legumes, and seeds — with animal protein. As for animal sources of zinc, such as red meat, poultry, and shellfish? Since they're already sources of protein, you can eat them solo without thinking about having to pair zinc plus protein.
Fat-Soluble Vitamins + Fat
The body stores vitamins A, D, E, and K in fatty tissue. These vitamins also need fat from food in order to be absorbed by the body, according to a review in the journal The Clinical Biochemist Reviews. These vitamins are collectively known as fat-soluble vitamins. This doesn't mean you should start cooking all your meals in bacon grease. Instead, you'll want to opt for "good" unsaturated fats such as omega-3 and omega-6 fatty acids instead; these fats can help lower LDL ("bad") cholesterol levels and high blood pressure, two major risk factors for heart disease, explains Figueroa. So, by pairing heart-healthy fats with fat-soluble vitamins, you can reap the benefits of improved vitamin absorption and cardiovascular protection.
When it comes to food pairings, the possibilities here are endless. Fat-soluble vitamins are abundant in fruits and veggies, while unsaturated fats can be found in foods such as fatty fish, nuts, and seeds. Some foods even naturally contain both fat and some fat-soluble vitamins, such as eggs, which have unsaturated fats and vitamin A, according to Harvard T.H. Chan School of Public Health.