Key Takeaways
Why Nutrient Gaps Are So Common in the U.S.
The typical American diet tends to be high in processed foods, refined grains, and added sugars — and relatively low in the fruits, vegetables, legumes, and dairy that deliver essential micronutrients. The result is a pattern that meets calorie needs but routinely falls short on specific vitamins and minerals that the body depends on for long-term health.
Federal nutrition surveys, including data from the National Health and Nutrition Examination Survey (NHANES), have repeatedly identified a handful of nutrients that a significant portion of the U.S. population under-consumes. These are sometimes called "nutrients of public health concern" because their shortfalls are widespread enough to have population-level consequences.
If you're newer to thinking about your diet in this way, the foundational nutrition guide is a useful place to start before diving into specific deficiencies. Below, we break down the most commonly missing nutrients — what each one does, and which everyday foods deliver it.
Dietary Fiber
Most Americans consume roughly half the recommended amount of dietary fiber. Fiber supports healthy digestion, helps regulate blood sugar levels, and is associated with reduced risk of cardiovascular disease and colorectal cancer. It also promotes satiety, making it easier to maintain a healthy weight over time.
Where to find it: Beans and lentils, whole grains (oats, barley, whole wheat), fruits with edible skins (apples, pears), vegetables (broccoli, Brussels sprouts), and nuts and seeds are among the richest sources.
Most Americans get roughly half the fiber their body needs each day.
Potassium
Potassium is essential for maintaining healthy blood pressure and supporting proper muscle and nerve function. Despite its importance, surveys show that the vast majority of Americans fall well below adequate intake levels — a gap made worse by high sodium consumption, which can offset potassium's blood-pressure benefits.
Where to find it: Bananas are well-known, but beans, lentils, potatoes (with skin), leafy greens, avocados, and yogurt are often even richer sources of potassium.
High sodium intake can offset potassium's blood-pressure benefits, making the gap doubly significant.
Calcium
Calcium is the primary mineral in bones and teeth, and it also plays a role in muscle contraction and nerve signaling. Inadequate intake over time contributes to reduced bone density, increasing the risk of fractures and osteoporosis — especially in women and older adults. Many Americans, particularly those who avoid dairy, don't meet recommended intake levels.
Where to find it: Dairy products (milk, cheese, yogurt) are the most concentrated sources. Non-dairy options include fortified plant-based milks, canned salmon or sardines with bones, tofu made with calcium sulfate, and leafy greens like bok choy and kale.
Inadequate calcium intake over time is a key contributor to bone density loss and fracture risk.
Vitamin D
Vitamin D supports calcium absorption, immune function, and muscle health. Because few foods naturally contain meaningful amounts of it, and many Americans spend limited time outdoors in sunlight (the body's primary production route), vitamin D insufficiency is one of the most widespread shortfalls in the U.S. Darker skin tones, older age, and living at northern latitudes further increase risk.
Where to find it: Fatty fish (salmon, mackerel, tuna), egg yolks, and fortified foods — including most cow's milk and many plant-based milks and cereals — are the main dietary sources. A healthcare provider can test blood levels and advise whether supplementation is appropriate for you.
Few foods naturally contain vitamin D, making it one of the most widespread nutritional shortfalls in the U.S.
Magnesium
Magnesium is involved in more than 300 enzymatic reactions in the body, including energy production, protein synthesis, blood sugar regulation, and blood pressure control. Despite its broad importance, surveys suggest a substantial portion of Americans consume less than the estimated average requirement. Diets high in processed and refined foods tend to be particularly low in magnesium.
Where to find it: Dark leafy greens (spinach, Swiss chard), pumpkin seeds, black beans, almonds, whole grains, and dark chocolate (in modest amounts) are reliable dietary sources of magnesium.
Magnesium supports over 300 bodily reactions, yet many Americans fall short of adequate intake.
Vitamin A
Vitamin A supports vision — particularly night vision — as well as immune function and healthy skin and cell growth. While severe deficiency is rare in the U.S., surveys indicate that a meaningful share of Americans consume less than recommended amounts. It exists in two dietary forms: preformed vitamin A from animal sources, and provitamin A carotenoids (such as beta-carotene) from plant sources.
Where to find it: Liver and dairy products supply preformed vitamin A. Orange and yellow vegetables (sweet potatoes, carrots, winter squash), leafy greens, and red bell peppers are excellent sources of beta-carotene, which the body converts to vitamin A as needed.
Vitamin A exists in two dietary forms — and most Americans can improve intake from everyday plant sources.
Building a Diet That Fills the Gaps
No single food or supplement covers everything, and chasing individual nutrients in isolation can cause you to miss the bigger picture. Research consistently shows that overall dietary patterns — rather than isolated nutrient targets — are what drive long-term health outcomes. For a broader look at what those patterns look like in practice, see eating patterns that show up in healthy diet research.
Prioritize Food First, Then Consider Supplements
Whole foods deliver nutrients alongside fiber, antioxidants, and other compounds that work together in ways supplements can't fully replicate. Before reaching for a multivitamin or individual supplement, focus on diversifying your plate — especially increasing vegetables, legumes, and whole grains. If you suspect a significant deficiency, a registered dietitian or your primary care provider can run appropriate tests and guide you toward the right approach for your situation.
For a deeper look at how vitamins and minerals function in the body, the micronutrients guide offers plain-language explanations of each one. And because hydration affects how your body absorbs and uses nutrients, it's worth reviewing how water fits into everyday nutrition as well.
This article is for general informational and educational purposes only and does not constitute medical or dietary advice. Speak with a qualified healthcare professional or registered dietitian before making significant changes to your diet or starting any supplement regimen.