4 essential nutrients you might be missing

First, the bad news: Most people in the world aren’t getting enough micronutrients. And, according to the 2020-2025 Dietary Guidelines for Americans, four are particularly scarce: calcium, potassium, dietary fiber, and vitamin D. The good news? They’re all readily available in various foods, for people with all different palates and budgets. (Nope, caviar or some endangered tree fruit aren’t the only sources.) Read on to learn why these nutrients are important for good health, get expert advice for boosting your intake through meals, and learn when you may need to bring in supplements.

Potassium

What it is and why it matters

Potassium does double duty as a mineral and an electrolyte. It helps power nearly every process in our bodies, supporting kidney health and playing 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., CDN. “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 your blood pressure: Whereas sodium constricts blood vessels — causing the body to have to work harder to transport blood and oxygen — potassium helps optimize blood flow. Decreasing sodium intake and increasing potassium intake may even help lower the risk of hypertension and heart disease.

Are you getting enough?

The daily recommended intake of potassium is 2,600 mg to 3,400 mg per day for adults, depending on your age, sex, and other factors (like pregnancy). “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., LDN., a registered dietitian at Emory University Hospital.

How to get more

Potassium is found 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.

A few foods especially high in potassium include these MVPs: spinach (1,180 mg per 1-cup serving, cooked), lentils (731 mg per 1-cup serving), and bananas (422 mg per medium banana).

Don’t love any of those? Try eating more leafy greens, avocados, fortified dairy and nondairy alternatives, animal protein sources (including broth and stock), edamame, nuts, potatoes, squash, broccoli, sweet potatoes, tomatoes, brown rice, and 100% whole-grain breads and pastas.

Fiber

What it is and why it matters

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 to get a steady stream of energy from our food, and sweep food through our gastrointestinal tract. (That last one is why fiber is probably most known for helping prevent constipation.) Certain types of fiber also offer a prebiotic function, meaning they feed the good bacteria in our intestines. This helps our digestive systems better absorb other nutrients and helps prevent the growth of harmful bacteria.

Along with helping digestion, people who eat more fiber have a reduced risk of cardiovascular disease, type 2 diabetes, and some cancers, and lower body weight. The last one is because foods with more fiber can help you feel full longer so you eat less.

Are you getting enough?

The USDA’s Dietary Guidelines for Americans recommends that adults consume between 22 grams and 34 grams of fiber per day, depending on age and sex. Generally, you want to get 14 grams of fiber for every 1,000 calories you eat. Yet more than 90% of women and 97% of men in the U.S. aren’t hitting those numbers.

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

It’s best to get your fiber from whole foods than from fiber supplements. That’s because supplements don't provide the different types of fiber that whole foods can. That said, if you're having trouble getting enough or are experiencing constipation, a supplement may help. Research shows that psyllium husk — a natural fiber supplement that comes in powder or tablet form — is associated with improved regularity and weight loss.

In terms of diet, Majumdar recommends adding more fiber 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.

One word of warning if you’re just embarking on that high-fiber lifestyle: start slow. Going from a low-fiber diet to a high-fiber one quickly can lead to gas, diarrhea, cramping, and bloating, so you’re better off slowly increasing how much fiber you eat over the course of a few weeks. And make sure to drink lots of water, which can help some types of fiber work better and can prevent uncomfortable bowel movements.

Calcium

What it is and why it matters

We’re born with calcium in our bodies, and we store about 99% of it in our bones and teeth. The mineral, the most abundant one in our bodies, is indispensable to nearly all cellular functions, especially those of muscles, nerves, and glands, London says. Plus, getting enough calcium may help reduce the risk of osteoporosis.

When you don’t intake enough calcium, the body draws from its stash in the skeletal system. 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 fractured bones, particularly in the hip, spine, and wrist.

Are you getting enough?

For most adults, the recommended daily intake of calcium is 1,000 mg. This number increases to 1,200 mg for women starting at age 51, and applies to men as well at age 71 and up. Yet 60% of women and close to 30% of men don’t get enough calcium.

People who are part of certain groups tend to be more likely to be low in calcium: People who are Black or Asian, postmenopausal women, teens, people who don’t eat dairy products, and those who are 50 years and older who are living in poverty.

How to get more

Dairy products like milk, cheese, and yogurt are typically the first foods that jump to mind when people consider calcium. And while they do contain high amounts of calcium, dairy isn’t the only option. 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., RDN, 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 non-dairy food sources of calcium include dark green leafy vegetables (kale, broccoli, bok choi), tofu, fortified cereals and fruit juices, and fortified plant-based beverages.

If you’re not getting enough calcium through food, you may want to discuss with your healthcare provider whether calcium supplementation may be right for you. There are two kinds: calcium carbonate and calcium citrate. The carbonate version (which you’ll find as a supplement, as well as in Tums and Rolaids) is absorbed best when taken with food. The citrate version can be taken on a full or empty stomach, and is better absorbed by people with lower levels of stomach acid, which happens to many people as they age.

Annoyingly, you can’t just pound a 1,000 mg calcium supplement and call it good. That’s because our bodies absorb calcium better when it’s 500 mg or less at one time, so it’s better to spread it out over the day.

Calcium absorption is also helped by Vitamin D, which most people are also low on — more on that below.

Vitamin D

What it is and why it matters

Since vitamin D works hand in hand with calcium, getting enough of both nutrients is crucial for maintaining and regulating bone mineral density, says London. Vitamin D also supports bone health, is essential for muscle and nerve function, and may play a role in immunity, cardiovascular health, and diabetes management.

Are you getting enough?

Probably not. More than 90% of people don’t hit the daily recommendation for vitamin D. Most people in the U.S. are consuming just 4 mcg or so of vitamin D per day. Yet the recommended daily intake for people through age 70 is 15 mcg/600 IU. For people over age 70, the recommendation increases to 20 mcg/800 IU per day.

Not getting enough vitamin D can lead to weak bones, muscle pain or weakness, mood changes, or general fatigue, Majumdar says.

How to get more

Unfortunately, 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. Not into fish? Eggs have some (1 mcg per large egg) vitamin D, as do fortified foods like milk, breakfast cereals, and orange juice. If you feel like you may not be getting sufficient vitamin D in your diet or your bloodwork shows a vitamin D deficiency, consider discussing with your healthcare provider if supplementation may be right for you.

A cool feature of vitamin D, and one that’s unique to the four nutrients on this list, is that your body can actually make some on its own when you get direct sunlight exposure on your skin. There’s no magic number for how long you should catch some rays to achieve enough vitamin D, but research suggests getting outside for a short period each day is generally sufficient — 5 to 10 minutes, two or three times per week — though sunlight through a window doesn't count. That said, your skin’s melanin content (people with darker skin tones tend to create less vitamin D from the same amount of sun exposure), age, location, and the time of year can all affect how much vitamin D you make.

Nope, this isn’t a recommendation to lounge outdoors sans sunscreen, which can raise your chances of skin cancer. Applying a broad-spectrum SPF 15 sunscreen reduces your risk of skin damage from the sun’s UV rays and still lets in 7 percent of the solar UVB reaching your skin, a good way to balance protection and exposure.

The bottom line

Many adults in the U.S. aren't getting enough calcium, potassium, dietary fiber, and vitamin D, which can impact their health and longevity. Try adding whole foods that contain these “core four” to get more of them in your diet.