National Vitamin C Day on April 4 celebrates one of the most useful nutrients in the human diet, a vitamin our bodies famously cannot make or store, which is why we need a steady supply from food. Vitamin C, or ascorbic acid, is essential for building collagen, healing wounds, absorbing iron, and defending cells as an antioxidant. Scurvy, the disease of severe deficiency, is a vivid historical reminder of just how much depends on it.

Get it from your plate first

The good news is that vitamin C is easy to come by if you eat a reasonably varied diet. Citrus gets the fame, but bell peppers, strawberries, kiwi, broccoli, and Brussels sprouts are all excellent sources, often beating oranges gram for gram. Because the vitamin is water-soluble and degrades with heat, eating some produce raw or lightly cooked preserves more of it. A single red bell pepper or a cup of strawberries can cover a day’s needs, so there is rarely a reason to reach for a supplement first.

More is not always better

Vitamin C is safe across a wide range, but megadosing has real limits. Your body absorbs a smaller fraction as the dose climbs and simply flushes the excess, and very large amounts can cause stomach upset or, in some people, contribute to kidney stones. There is also no strong evidence that loading up on vitamin C prevents the common cold, though it may modestly shorten one. If you supplement, a modest dose is plenty, and buffered or effervescent forms are gentler on the stomach.

A pairing worth knowing

One genuinely useful trick is that vitamin C dramatically boosts the absorption of plant-based iron. Squeezing lemon over lentils or eating strawberries alongside a spinach salad helps your body take up more of the iron in those foods, which matters especially for people who eat little or no meat. On the skin-care side, a topical vitamin C serum is a well-supported ingredient for brightening and antioxidant protection, and it pairs naturally with daily sunscreen. Store both citrus and serums away from heat and light so they keep their potency.

Vitamin C Day is a fun excuse to appreciate a workhorse nutrient, but the real lesson is undramatic: eat colorful produce most days and you are almost certainly covered. Supplements and serums have their place, but the produce aisle does most of the job. Slice an orange, roast some peppers, and call it a celebration.

How to celebrate

  1. 1
    Eat the rainbow

    Bell peppers, strawberries, kiwi, and broccoli often beat oranges for vitamin C. Aim for a variety of colorful produce most days.

  2. 2
    Keep some raw

    Vitamin C degrades with heat and light, so eat some produce raw or lightly cooked. Store citrus away from warmth to preserve it.

  3. 3
    Pair with iron

    Squeeze lemon over lentils or add strawberries to a spinach salad. Vitamin C dramatically boosts your absorption of plant-based iron.

  4. 4
    Skip the megadose

    Your body absorbs less as the dose climbs and flushes the rest. A modest amount is plenty, and very large doses can upset your stomach.

  5. 5
    Try a vitamin C serum

    A topical serum is a well-supported step for brightening and antioxidant protection. Layer it under your morning sunscreen.