Plant-Based Eating Without Deficiency: A Practical Checklist

The evidence that thoughtfully-planned plant-based diets are healthful at a population level is broadly consistent. The evidence that poorly-planned plant-based diets can produce specific nutrient gaps is also consistent. Both are true, and neither is interesting on its own. What is interesting is the short list of nutrients that genuinely need planning, and the much shorter list that needs supplementing.

The 'must supplement' list

Vitamin B12

There is no reliable plant source of vitamin B12. Fortified plant milks, nutritional yeast, and some fortified cereals are options, but daily supplementation (or several-times-weekly higher-dose supplementation) is the simplest insurance. The major dietetic associations are unanimous on this point. Methylcobalamin or cyanocobalamin both work; doses of 25–100 mcg daily, or 1,000 mcg twice weekly, are reasonable for adults.

Omega-3 (EPA and DHA)

ALA (in flax, chia, walnuts) is converted to EPA and DHA inefficiently in humans. For plant-based eaters who want to cover the EPA/DHA bases without fish, algal-oil supplements are the cleanest solution. 250–500 mg combined EPA+DHA per day matches the dose found beneficial in mixed-diet research.

The 'plan, then verify' list

Iron

Plant iron is non-heme and absorbs less efficiently than animal iron, but the gap is largely closed by including a vitamin-C source at meals and moving coffee and tea away from food. Premenopausal women, endurance athletes, and frequent blood donors should test ferritin periodically. Our iron-rich foods piece covers the practical pairings.

Zinc

Found in legumes, whole grains, nuts, seeds, and tofu; absorption is modestly reduced by phytate. Soaking and sprouting beans and grains improves bioavailability. Most plant-based eaters meet requirement; vegans with restrictive eating patterns are the population at most risk.

Calcium

Without dairy, calcium becomes a deliberate target. Fortified plant milks (typically 300 mg per cup, similar to cow's milk), tofu set with calcium sulfate, low-oxalate greens (kale, bok choy, broccoli), and almonds are the main sources. Most adults need ~1,000 mg/day. Two cups of fortified plant milk plus one calcium-set tofu serving plus some greens covers it; without those, the gap is real.

Iodine

Iodine is the under-appreciated micronutrient on plant-based diets. Without dairy or eggs, iodine intake drops sharply. Iodised salt (where available) and the occasional inclusion of seaweed (nori, dulse, wakame — kelp is too high) covers requirements. A modest iodine supplement is reasonable for people who use unsalted plant-based diets long-term.

Vitamin D

Plant-based or not, most adults in temperate climates benefit from vitamin D supplementation in winter. The same advice applies as in our vitamin D guide: 1,000–2,000 IU/day for most adults; check status if unsure.

Protein, briefly

Total protein on a plant-based diet is achievable without difficulty, but it does require some attention. Leucine — the amino acid that appears to threshold muscle protein synthesis — is somewhat lower in plant proteins than in animal proteins. The practical solution is to include leucine-rich sources at most meals: soy products (tofu, tempeh, soy milk), lentils, hemp seeds. Active adults targeting muscle gain on a plant-based diet usually do well at the higher end of the protein range (2.0–2.2 g/kg) with leucine-rich sources at every meal.

What a covered day looks like

• Breakfast: oatmeal cooked with fortified soy milk, ground flax, berries, walnuts.
• Lunch: lentil and roasted vegetable bowl with tahini and lemon, side salad with peppers.
• Snack: fortified plant yoghurt with seeds.
• Dinner: tofu stir-fry with broccoli, brown rice, sesame seeds, plus a small piece of dark chocolate.
• Daily: B12 supplement, algal omega-3, vitamin D in winter, iodised salt in cooking.

When to track

A two-to-four week period of careful tracking when transitioning to a plant-based diet is one of the most useful things you can do. The goal is not to track forever; it is to verify that what you are actually eating covers calcium, iron, zinc, B12, and omega-3 — and to find any gaps before they become deficiencies six months in. Apps that surface micronutrient totals — Cronometer, NutriShot AI, and other tools in that bracket — make this verification far easier than it once was.