Updated April 2026 · Reviewed by the Online Nutrition Planet editorial team

Most discussions of nutritional deficiencies focus on the usual suspects — iron, calcium, vitamin D. But there's a second tier of nutrients that are commonly under-consumed and rarely discussed, even in otherwise varied diets. This guide covers five of the most commonly neglected nutrients, why they matter, and how to get more of them.

Medical disclaimer: This article is general education. Consult a healthcare provider before starting any supplement regimen.

1. Magnesium

Magnesium is involved in over 300 enzymatic reactions in the body — muscle function, nerve transmission, blood sugar regulation, blood pressure control, protein synthesis, and bone formation. Despite being so important, roughly half of American adults fall short of recommended intakes.

Why it's neglected: Magnesium-rich foods (leafy greens, nuts, seeds, whole grains, legumes) are exactly the foods most Americans eat too little of. Refined grains lose most of their magnesium during processing.

Best food sources: Pumpkin seeds, almonds, cashews, spinach, black beans, edamame, dark chocolate, quinoa, oatmeal, avocados.

Signs of low intake: Muscle cramps, fatigue, irritability, difficulty sleeping, headaches.

2. Potassium

Potassium balances sodium levels, supports healthy blood pressure, regulates fluid balance, and is essential for muscle and nerve function. The recommended intake for adults is 4,700 mg daily — most Americans get about half that.

Why it's neglected: Most people don't realize potassium comes primarily from fruits and vegetables, not just bananas. Low fruit and vegetable intake directly causes low potassium.

Best food sources: Sweet potatoes, beans, lentils, spinach, tomatoes, bananas, oranges, yogurt, salmon, avocados, winter squash.

Signs of low intake: Elevated blood pressure, muscle weakness, cramps, fatigue, heart rhythm irregularities in severe cases.

3. Fiber

Technically a carbohydrate, but important enough to count as its own category. Fiber supports digestive regularity, feeds beneficial gut bacteria, moderates blood sugar, and promotes satiety. Recommended intake is 25 grams daily for women and 38 grams for men under 50. Most Americans get about 15 grams.

Why it's neglected: Fiber comes from plant foods — fruits, vegetables, legumes, whole grains. The standard American diet is heavy on refined grains, processed foods, and animal products that contain no fiber at all.

Best food sources: Beans, lentils, chickpeas, oats, whole grains, berries, apples, pears, broccoli, Brussels sprouts, nuts, seeds.

Signs of low intake: Constipation, irregular bowel movements, blood sugar swings, increased hunger between meals.

4. Choline

Choline is essential for liver function, brain development, nerve signaling, and muscle function. Recommended intake is 425 mg for women and 550 mg for men. Most Americans don't meet these targets. During pregnancy, adequate choline is critical for fetal brain development — covered in detail in our prenatal nutrition guide.

Why it's neglected: Choline wasn't officially classified as an essential nutrient until 1998, and it rarely appears on food labels or in nutrition education materials. Egg yolks are the richest common source, but people often avoid them due to outdated cholesterol fears.

Best food sources: Egg yolks (a single egg provides about 25% of daily needs), beef liver, chicken, fish, beef, Brussels sprouts, broccoli, shiitake mushrooms, beans.

Signs of low intake: Fatty liver disease risk, muscle damage, cognitive concerns in developing children.

5. Omega-3 fatty acids (EPA and DHA)

The long-chain omega-3 fatty acids EPA and DHA support brain function, eye health, cardiovascular health, and inflammation regulation. Most Americans don't consume enough — especially those who rarely eat fatty fish.

Why it's neglected: EPA and DHA come primarily from fatty fish. Plant sources (flax, chia, walnuts) contain ALA, which converts to EPA/DHA at very low rates (under 10% to EPA, under 1% to DHA). People who don't eat fish regularly — including strict vegans — often have low EPA/DHA status.

Best food sources: Salmon, sardines, mackerel, anchovies, herring, trout. Algae-based supplements for plant-based eaters.

Signs of low intake: Dry skin, cognitive concerns, higher inflammation markers, worse cardiovascular risk profile.

How to cover these five nutrients

The encouraging thing about these five neglected nutrients is that you can cover all of them with the same general dietary approach:

  • Eat leafy greens and vegetables at most meals (magnesium, potassium, fiber)
  • Include legumes and beans several times a week (fiber, magnesium, potassium)
  • Choose whole grains over refined grains (magnesium, fiber)
  • Eat eggs regularly (choline)
  • Include fatty fish 1–2 times per week (EPA/DHA) or take an algae-based supplement
  • Eat nuts and seeds daily (magnesium, fiber)

This is essentially a Mediterranean-style or whole-food plant-forward eating pattern. The nutrients that are commonly neglected are the same nutrients that come bundled with the eating patterns that have the strongest evidence base for long-term health.

The bottom line

Magnesium, potassium, fiber, choline, and omega-3 EPA/DHA are five commonly under-consumed nutrients in the standard American diet. Addressing them doesn't require expensive supplements or obsessive tracking — it requires eating more vegetables, fruits, legumes, whole grains, nuts, seeds, eggs, and fatty fish. The same dietary pattern that covers these nutrients supports general health broadly.

For personalized assessment of your specific nutrient status, blood work ordered through a healthcare provider is more reliable than guessing. A registered dietitian can help interpret results and build a targeted eating plan. See our online nutrition coach reviews for options.

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Written by the Online Nutrition Planet editorial team. Questions? Contact us.

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