Key Takeaways:

• McCollum and Simmonds incorporate the then‑new science of vitamins and minerals into practical dietary advice for maintaining health.
• They show how specific nutrient deficiencies lead to characteristic diseases, shifting nutrition from vague advice to measurable requirements.
• The book emphasizes whole, varied diets and warns that refining and processing can strip foods of essential micronutrients.
• Nutrition is framed as preventive medicine: correctly chosen foods can avert illness long before symptoms appear.