OK, considering the sheer number of nutrients and micronutrients available in the human diet—about three dozen altogether—many of us are doing a pretty decent job at consuming adequate amounts of most of them. Still, in the recently released 2020-2025 Dietary Guidelines for Americans, four essential nutrients were namechecked as needing some extra attention.
In the report, calcium, potassium, dietary fiber, and vitamin D were all identified as underconsumed in the U.S., which means you might not be getting the amount your body needs to function at its best. The good news: Boosting your intake of these nutrients is simple—not to mention delicious!—once you know which foods contain them.
Read on to learn why these four nutrients are important for good health, along with expert advice for boosting your intake and helpful information on dietary supplements in case you need extra support.
As a mineral and an electrolyte, potassium helps power nearly every process in our bodies. It supports kidney health and plays a significant role in nerve and muscle function. Potassium is also critical for maintaining healthy blood pressure, explains registered dietitian Jaclyn London, M.S., R.D., C.D.N. “It’s the primary biochemical ‘counterbalance’ to sodium, which the Dietary Guidelines identify as an over-consumed nutrient in the U.S.—largely through salty foods,” London notes. Here’s how potassium helps: Whereas sodium constricts blood vessels—causing the body to work harder in transporting blood and oxygen—potassium helps optimize blood flow. A 2013 review published in the Mayo Clinic Proceedings found that decreasing sodium and increasing potassium may help lower the risk of hypertension and heart disease.
Potassium intake in the U.S.
The daily recommended intake of potassium is 2,600 mg to 3,400 mg per day for adults, depending on sex. As for how much we’re actually getting, women over the age of 20 consume 2,324 mg per day on average, compared to men’s 2,937 mg, according to the 2017–2018 National Health and Nutrition Examination Survey (NHANES).
At the population level, that means we’re not too far off the mark. Still, it pays to stay on top of intake. “Not eating enough potassium may cause muscle weakness or tingling, and could contribute to high blood pressure, fatigue, irregular heart beat, and more,” says Melissa Majumdar, M.S., R.D., L.D.N., a registered dietitian and national spokesperson for the Academy of Nutrition and Dietetics.
How to get more potassium in your diet
Potassium is abundant in many fruits, vegetables, dairy products, and whole grains—food groups that many adults in the U.S. tend to skimp on, according to the Dietary Guidelines. This means you likely have lots of new options for boosting the potassium in your diet: Try incorporating leafy greens, avocados, fortified dairy and nondairy alternatives, animal protein sources (including broths and stocks), edamame, nuts, potatoes and sweet potatoes, tomatoes, brown rice, and 100% whole-grain bread and pasta to your daily meals and snacks. A few foods especially high in potassium include spinach (1,180 mg per 1-cup serving, cooked), lentils (731 mg per 1-cup serving), and bananas (422 mg per medium banana).
Dietary fiber is a type of carbohydrate found in plants. Unlike with other nutrients, which the body breaks down and absorbs, we lack the enzymes needed to digest fiber. As a result, fiber helps fill us up, stabilize the rate of digestion for a steady energy release from food, and keeps contents moving through the gastrointestinal tract with a broomlike effect. (That last one is why fiber is probably most famous for helping prevent constipation!) Certain types of fiber also offer a prebiotic function—they feed the “good” bacteria in our intestines. This helps our digestive system better absorb other nutrients and helps prevent the growth of harmful bacteria.
Alongside the digestive pros, diets higher in fiber are associated with a slew of health protections, including reduced risk of cardiovascular disease, certain cancers, and type 2 diabetes. Plus, if your health and wellness goals include weight loss, a 2013 review published in Nutrients found that a higher fiber intake was associated with lower body weight.
Fiber intake in the U.S.
The Institute of Medicine recommends that adults consume between 21 g and 38 g of fiber per day, depending on age and sex. According to the NHANES, many people in the U.S. are putting far less on their plates—for men, about 18 g a day, with women getting just 16 g of fiber.
Although fiber is a key element of an overall healthy pattern of eating, there’s no established deficiency level. Some signs that you may want to amp up your intake include constipation and feelings of hunger shortly after meals.
How to get more fiber in your diet
Majumdar recommends adding more fiber to your diet through fruits, vegetables, whole grains, nuts, beans, and lentils. Some especially high-fiber foods include black beans (15 g per 1-cup serving), green peas (9 g per 1-cup serving), and whole-wheat spaghetti (6 g per 1-cup serving). Another pro tip: Whenever possible, leave the peel on your produce—the skin on fruit and veggies (from potatoes to apples) provides a boost of fiber.
About 99% of the body’s calcium is stored in our bones and teeth—in fact, it’s essential for supporting their structure. But calcium isn’t just about maintaining strong bones and a stellar smile. The mineral is indispensable to nearly all cellular functions, especially those of muscles, nerves, and glands, London says.
Calcium intake in the U.S.
For most adults, the recommended daily intake of calcium is 1,000 mg. This number increases to 1,200 for women at and above age 51, and all adults at age 71. That said, many of us are not meeting those targets. The NHANES found men and women over the age of 20 are consuming just 966 mg of calcium per day on average.
When calcium levels dip, the body draws from its stash in the skeletal system, London explains. Over the long term, this can deplete bone mass and raise a person’s risk of developing osteoporosis. The result can be a heightened susceptibility to bone breaks, particularly in the hip, spine, and wrist.
How to get more calcium in your diet
Dairy products are typically the first foods that jump to mind when people consider calcium, which makes sense! Those foods do contain high amounts of the nutrient. You may be surprised to learn, however, that milk, cheese, and yogurt aren’t your only options. Case in point: a 1-cup serving of cooked collard greens delivers 324 mg calcium, slightly more than 322 mg you’d get in an equal-size serving of skim milk.
You can also find calcium in canned fish with soft bones, explains Jerlyn Jones, M.S., M.P.A., R.D.N., L.D., C.L.T., owner of The Lifestyle Dietitian and a spokesperson for the Academy of Nutrition and Dietetics. A 3.75-oz can of sardines (drained with bones) contains 351 mg of calcium. Other food sources include dark green leafy vegetables, tofu, fortified cereals and fruit juices, and fortified plant-based beverages.
Vitamin D works hand in hand with calcium, so getting enough of both nutrients is crucial for maintaining and regulating bone mineral density, says London. Vitamin D helps your body absorb calcium and manage levels to maintain a balance in your system. In addition to its role in supporting bone health, vitamin D is essential for muscle and nerve function, and may play a role in immunity, cardiovascular health, and diabetes management.
Related: Here’s what we know about COVID-19 and vitamin D
Vitamin D intake in the U.S.
The recommended daily intake of vitamin D for people between the ages of 1 and 70 is 15 mcg. For people over age 70, the recommendation increases to 20 mcg per day. People in the U.S. over the age of two are consuming just 4 mcg or so of vitamin D per day, according to the NHANES. The health implications of too little vitamin D include weak bones, muscle pain or weakness, mood changes, and/or general fatigue, Majumdar says.
How to get more vitamin D in your diet
Admittedly, vitamin D is one of the more difficult nutrients to get through food alone. Good sources include fatty fish such as salmon (31 mcg per medium-sized fillet), trout, tuna, and mackerel, Jones says, with eggs being a decent source, as well (1 mcg per large egg). Grocery items commonly fortified with vitamin D include milk, breakfast cereals, and orange juice.
A unique feature of vitamin D is that your body can make its own: Direct sunlight exposure on skin triggers vitamin D synthesis. There’s no magic number for how long you should catch some rays to achieve optimal vitamin D status, but research suggests getting outside for a short period each day is generally sufficient. In summer months, that can be as little as 5 to 15 minutes, two or three times per week, according to the World Health Organization. That said, your skin’s melanin content, your age, the season, and certain weather conditions can all affect vitamin D production. And remember to apply a broad-spectrum sunscreen of SPF 15 or higher before heading outdoors to reduce the risk of skin damage from the sun’s ultraviolet rays.