Metaphor I learned from a biochemist: You are in a boat with holes in it (holes in this metaphor are nutritional deficiencies). To prevent the boat from sink

Metaphor I learned from a biochemist: You are in a boat with holes in it (holes in this metaphor are nutritional deficiencies). To prevent the boat from sinking you patch the holes under waterline starting from the largest. The boat continues to sink until all holes under the waterline are patched. You don't stop sinking by patching one hole again and again. After you have patched all holes under the waterline you can prepare for storm (old age, sickness) and patch holes above the waterline. You should start from the lowest and go upward. lessons: 1. Measure. Blood test can determine if you have deficiencies you need to fix. 2. Once you have fixed one deficiency, fixing it by taking more does not help. 3. Fancy nutrients (phytonutrients, Omega-3) have very tiny effect size if it exists at all. They would be at the bottom of any list (healthy diet, exercise, sleep, right weight). If you don't get enough sleep your immune system and cognition are compromised and supplements don't compensate. ---- ps. Body can synthesize omega-3 if there is enough α-linolenic acid (ALA) available. Aging may impair body's ability to make omega−3 fatty acids from ALA. _IF_ this is the case, omega-3 supplements _may_ help.