Plant-Based and Vegan Diets

Spectrum

• Vegan: no animal-source foods.
• Lacto/ovo vegetarian: includes dairy/eggs.
• Pescatarian: adds fish/seafood.
• “Plant-based”: mostly plants, allowing small amounts of animal foods.

What the evidence shows

• Adventist Health Study and EPIC-Oxford show lower BMI, lower cardiovascular mortality, lower type-2 diabetes incidence in vegetarians vs. meat-eaters in matched cohorts.
• Quality matters: a vegan diet of refined grains, sugar, and processed vegan foods has different effects than one built on whole foods (Satija et al.).
• Predominantly plant-based diets reliably lower LDL, blood pressure, and inflammatory markers.

Nutrient watch-points

• Vitamin B12 — absent from plant foods; supplementation or fortified foods required for vegans, recommended for many vegetarians.
• EPA/DHA — minimal in plant foods; algae-based supplements available.
• Iron — non-haem iron is less bioavailable; pair plant-iron sources with vitamin C.
• Zinc, iodine, choline — can be lower; plan intentionally.
• Calcium, vitamin D, vitamin K2 — especially relevant in older vegan adults.
• Protein — achievable on plant-only diets with attention to total intake and leucine; older adults need to plan more carefully.

Practical guidance

Whatever the label, a diet built on vegetables, legumes, nuts, whole grains, and (if included) fish or fermented dairy will outperform most alternatives for cardiometabolic aging.

Related entries

Mediterranean diet, Protein and mTOR, Cardiovascular disease.