A well-planned vegan diet can be healthy and offers measurable benefits for heart health and metabolic function. But “well-planned” is doing real work in that sentence. Without attention to a handful of key nutrients, a vegan diet carries genuine risks for bone health, energy levels, and neurological function. The honest answer is that going vegan is healthy if you treat supplementation and food variety as non-negotiable parts of the diet, not afterthoughts.
Where Vegan Diets Shine: Heart Health
The cardiovascular benefits of plant-heavy eating are some of the most consistent findings in nutrition research. A large study through the Million Veteran Program found that people eating more healthful plant-based foods had a 16 to 17% lower risk of cardiovascular disease overall. That included a 19% lower risk of fatal cardiovascular events and a 14% lower risk of heart attack and stroke. These numbers held up after adjusting for other lifestyle factors.
The mechanism is straightforward. Plant-based diets tend to be higher in fiber, lower in saturated fat, and rich in compounds that reduce inflammation and improve blood vessel function. People eating vegan also tend to have lower LDL cholesterol and lower blood pressure on average. These aren’t small differences. Over decades, they translate into meaningfully lower risk of the conditions that kill the most people in developed countries.
The B12 Problem Is Real
Vitamin B12 is the nutrient vegans are most likely to become deficient in, and the consequences are serious. B12 is essential for nerve function, red blood cell production, and DNA synthesis. It occurs naturally almost exclusively in animal products.
A study of 151 vegans in the Czech Republic found that 15% were B12 deficient based on blood levels alone. When researchers used a more sensitive combination of markers, 16.9% of vegans showed signs of deficiency. The breakdown by supplement use was striking: only 5.6% of regular supplement users were deficient, compared to 52.9% of those who took no supplements at all. That’s more than half of non-supplementing vegans showing laboratory signs of deficiency.
B12 deficiency doesn’t always announce itself quickly. It can take years for stores to deplete, and early symptoms like fatigue, tingling in the hands and feet, and difficulty concentrating are easy to dismiss. Left untreated, it can cause irreversible nerve damage. The fix is simple: take a B12 supplement. For vegans, a daily dose of 50 to 100 micrograms is commonly recommended for prevention, well above the general population guideline of 2.4 micrograms per day, because absorption from supplements is less efficient than from food.
Iron: A Subtler Challenge
Iron deficiency is more common in vegans than omnivores, though the gap is narrower than many people assume. In the same Czech study, 11.6% of vegans showed signs of ongoing iron deficiency compared to 7.4% of non-vegans. Anemia rates were 13.6% among vegans, with women affected at more than three times the rate of men (21.4% versus 6.5%).
Plant-based iron (called non-heme iron) is absorbed less efficiently than the iron in meat. But you can improve absorption significantly by pairing iron-rich foods like lentils, chickpeas, tofu, and fortified cereals with vitamin C sources. A squeeze of lemon on your lentil soup or bell peppers in a stir-fry with tofu can roughly double the amount of iron your body takes up. Cooking in cast iron also adds measurable amounts to food.
Bone Health Deserves Attention
This is where the data gives the most pause. Vegans have roughly 6% lower bone mineral density at the hip compared to meat eaters, and the fracture risk numbers are hard to ignore. After adjusting for body weight and lifestyle factors, vegans in one large cohort had more than double the risk of hip fracture compared to meat eaters (a hazard ratio of 2.31). They also had 43% higher risk of fractures overall and double the risk of leg fractures.
The likely drivers are lower intakes of calcium, vitamin D, and protein, all of which are critical for maintaining bone density. Most adults need 1,000 mg of calcium per day (1,200 mg for women over 50 and everyone over 70). Getting that much from plants alone is possible but requires deliberate effort. Kale, broccoli, bok choy, and cabbage have calcium that’s absorbed at rates similar to milk, around 27%. But spinach, despite its calcium content, has only about 5% absorption because of compounds called oxalates that bind the mineral and prevent your body from using it.
Fortified plant milks and tofu made with calcium sulfate are the most practical ways to close the gap. If your daily intake consistently falls short, a calcium supplement is worth considering, particularly if you’re over 50 or have other risk factors for osteoporosis.
Muscle Building Works the Same Way
One common concern about going vegan is losing muscle or struggling to build it. Research from the University of Illinois put this to the test by assigning 40 physically active adults to either vegan or omnivorous diets while following the same weight-training program. Protein intake was moderate, around 1.1 to 1.2 grams per kilogram of body weight per day. The vegan meals were designed to include complete proteins by combining different plant sources.
The result: there was no difference in muscle protein synthesis between the two groups. The researchers noted that as long as total protein intake is adequate and includes a balanced amino acid profile, the source of that protein doesn’t appear to matter for building muscle. This held true regardless of whether protein was spread evenly across meals or eaten in larger amounts at fewer sittings.
The practical takeaway is that vegan athletes and recreational exercisers can build muscle just as effectively, but they need to be intentional about combining protein sources (rice and beans, soy products, seitan, lentils with grains) to get the full range of amino acids.
Pregnancy and Growing Children
Major health organizations consider a well-planned vegan diet safe during all life stages, including pregnancy, breastfeeding, infancy, and childhood. A research team comparing diet quality across omnivores, vegetarians, and vegans found nutrient gaps in every group, making it impossible to label any single diet as universally superior.
That said, pregnant vegans face a higher risk of falling short on B12, iron, iodine, zinc, omega-3 fatty acids, and protein. The research found no significant increase in severe adverse pregnancy outcomes, but the nutrient shortfalls are real and need to be addressed. A prenatal multivitamin, a plant-based DHA supplement (made from algae rather than fish oil), and attention to protein-rich foods throughout the day cover most of the bases.
For children, the key nutrients are the same ones adults need to watch, but the margin for error is smaller because growing bodies have higher nutrient demands relative to their size. B12 supplementation is especially important since deficiency during critical developmental windows can affect neurological development.
Nutrients to Supplement or Monitor
If you’re going vegan, these are the nutrients that require active management:
- Vitamin B12: Supplement daily. This is not optional. No reliable plant-based source exists in sufficient quantities.
- Calcium: Aim for 1,000 mg per day through fortified foods, low-oxalate greens, and supplements if needed.
- Vitamin D: Important for calcium absorption and bone health. Supplement during winter months or if you get limited sun exposure.
- Iron: Eat iron-rich plant foods with vitamin C. Get levels checked annually, especially if you menstruate.
- Omega-3 fatty acids: Consider an algae-based DHA/EPA supplement, since plant sources like flaxseed only provide a precursor that the body converts inefficiently.
- Iodine: Use iodized salt or eat seaweed in moderate amounts. Iodine intake can be unpredictably low on vegan diets.
The Bottom Line on Health
Going vegan is not automatically healthy, and it’s not automatically risky. The diet’s cardiovascular and metabolic benefits are well supported, and muscle building works fine with adequate protein. The real vulnerabilities are bone health and a small set of nutrients that require supplementation or careful food choices. A vegan who supplements B12, pays attention to calcium and iron, and eats a varied diet of whole foods is likely to be in excellent health. A vegan who treats the diet as simply “cutting out animal products” without replacing what those products provided is heading toward deficiencies that can take years to show symptoms but cause lasting damage.