Meat gives you complete nutrition without needing supplements
A vegan diet does need a reliable B12 source, and that is a real difference. But B12 is a single nutrient, fixed cheaply with fortified foods or a supplement. Much of the B12 in meat comes from supplements given to the animals, and omnivores already rely on iodised salt, fortified flour and fortified milk.
A diet that meets every need from ordinary food is more robust than one that depends on remembering a pill. People forget, can't afford supplements, or don't know they need them, and a B12 shortfall can do lasting harm before anyone notices. Meat, eggs and fish supply B12, well-absorbed iron, complete protein and long-chain omega-3 together, with no special knowledge required. That margin of safety is a real nutritional advantage.
Needing one supplement says something about one nutrient, not about whether a diet is adequate overall. In practice the list is short. B12 is essential. Vitamin D and iodine matter depending on sunlight and local soils, but those are concerns for omnivores too. Algal omega-3 is an option, not a requirement. Most of the other nutrients usually raised, such as protein, iron, vitamin A and K2, are covered by ordinary plant foods eaten in reasonable amounts.
The idea that meat lets you avoid supplements is less clean than it sounds. Farmed animals get B12 the same way vegans do, from bacteria. Modern livestock are routinely given cobalt or B12 in their feed, because intensive and grazing systems alike cannot rely on the soil to supply it. The supplement is still there. It has just been routed through an animal first.
Omnivore diets also depend on fortification without anyone calling them inadequate. Salt is iodised, flour is fortified with iron and folic acid in many countries, and milk and cereals carry added vitamins. Health bodies already advise many older adults to take B12 whatever they eat, because absorption from food declines with age. On fibre, many omnivore diets fall well short, and no pill fixes that as easily as a B12 tablet fixes the vegan gap.
The robustness concern is fair. A diet that forgets B12 can do real harm, so the advice should be stated plainly rather than played down. But a cheap, reliable fix for one nutrient is a planning detail. It is not a reason for meat to be a necessary part of a healthy diet, and necessity is the claim being made.
- Why take supplements when I could just eat lean meat like chicken, fish and turkey?
Different wording, same argument. The response above answers all of them.
Treating 'natural' as evidence of 'good', or 'unnatural' as evidence of 'bad'. Whether something occurs in nature tells you nothing about whether it is beneficial or right: hemlock, malaria and infant mortality are all perfectly natural.
How it applies here: The argument treats getting nutrients from whole animal foods as better in itself than getting them from a supplement or fortified food. It never says why a B12 tablet is worse than B12 that reached the animal through supplemented feed. Its unspoken premise is that the food route is more natural, and that being more natural makes it superior.