Although what you medically mention is true in part, there are also studies that provides solution to those lacks.
Veganism indeed lacks on the medical front as several studies suggest that vegan diet lacks in complete proteins, omega 3 fatty acids, many macro Nutritions, etc.
"Incomplete proteins in vegan diet"
While animal products contain all nine essential amino acids, plant-based sources can also provide complete proteins. A variety of plant foods, such as legumes, grains, nuts, and seeds, can be combined to ensure all essential amino acids are consumed. The concept of "protein combining"—eating complementary plant proteins in the same meal—is not necessary; consuming a variety of plant proteins throughout the day suffices.
A study published in ScienceDirect discusses the adequacy of plant-based diets, noting that individuals following such diets can meet their protein needs with proper planning.
The overall macro nutrients
Omega-3 fatty acids, particularly EPA and DHA, are primarily found in marine sources. However, vegans can obtain these essential fats through algae-based supplements. Microalgae produce DHA and EPA directly, serving as a sustainable and effective source for those avoiding animal products.
Research indicates that supplementation with algal DHA improves plasma and serum DHA concentrations and omega-3 indices in vegetarian populations.
OFF-TOPIC BUT IT'S NECESSARY
You can introduce the macros you lack via food supplements, which are not cheap in Italy but choosing the right ones can be useful and also can help you spending much less in food!
But okay let's move onto the moral perspective:
Supplements are expensive. Malnutritioned kids here in India are fed with eggs, the idea of Veganism is not poor friendly.
If you didn't mention the poor people, it could've been a much shorter debate.
Poor people are justified for the food choices that they made because they indeed need food which is accessible to their possibilities (their possibilities in capitalism of course, in the 2025 imo is totally nonsense that people are starving due economic situations, but that's another thing).
Said so, poor people are justified for the choices that they made, basic humanity I guess.
Sources
Protein Adequacy in Vegan Diets
- Protein Adequacy, Plant Protein Proportion, and Main Plant Protein Sources in Vegan Diets https://www.sciencedirect.com/science/article/pii/S0022316624004504
- Protein and Amino Acid Adequacy and Food Consumption by Processing Level in a Vegan Population https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2820203
Omega-3 Fatty Acids in Vegan Diets
- Achieving Optimal Omega-3 Fatty Acid Status in the Vegan Population https://nutritioninvestigator.org/wp-content/uploads/2024/04/41omega3.pdf
- Omega-3 Polyunsaturated Fatty Acids and Vegetarian Diets https://www.mja.com.au/journal/2013/199/4/omega-3-polyunsaturated-fatty-acids-and-vegetarian-diets
- Omega-3s – Vegan Health https://veganhealth.org/omega-3s-part-2/
you got painfully off topic talking about poor people, will explain better when I'll make the argument
is it enough also a small argument?