How could he have provided more convincing evidence of the relationship between pellagra and nutrition?

He could have provided more convincing evidence of the relationship between pellagra and nutrition by conducting controlled clinical trials that directly linked dietary deficiencies to the onset of the disease. Additionally, incorporating epidemiological studies that tracked dietary habits and prevalence rates of pellagra in different populations would strengthen his argument. Gathering testimonials and case studies from affected individuals regarding their nutritional intake prior to developing symptoms would also add personal insight and credibility to his findings. Finally, using biochemical analysis to demonstrate the impact of specific nutrient deficiencies on health could offer a more scientific basis for his claims.