I'm interested in making a list of how to best absorb specific nutrients. Whether or not we always want to best absorb each nutrient is debatable, but I think putting this information together could be really beneficial. I started with iron and calcium. If you know some others, let me know. It will be added and appreciated.
B Vitamins: Biotin absorption is decreased by avidin, an antinutrient in raw eggs (31). Cooking denatures avidin and increases biotin bioavailability.
Beta-carotene: Beta carotene (being fat soluble) is better absorbed with fat (13). Absorption is decreased by pectin (15) and helminths, apparently (14). I guess that's a good to thing to know if you're a fan of the hygiene hypothesis and were planning to eat an intestinal parasite to cure your allergies. (perhaps add distinction between vitamin A/beta-carotene?)
Calcium: Calcium absorption is increased by vitamin D (1), enough, but not too much, magnesium (2), soluble fibers like inulin (3), and dietary protein (4). Calcium absorption is decreased by whole wheat (5), fibers in fruits and vegetables like cellulose (6,7) and oxalic acid (8).
Iron: Iron absorption is increased by vitamin C (9) and decreased by phytic acid (11), calcium (23, 24), and tannins/phenolic compounds found in things like tea, coffee, and wine (10). Vitamin A and beta carotene appear to increase non-heme iron absorption by reducing the effect of phytic acid and polyphenols (25).
Protein: Egg protein is more digestible after cooking (21). Drinking a lot of water with a meal may decrease protein digestion by diluting hydrochloric acid in the stomach. I haven't seen any hard studies on this, but Chris Kresser has said this before and I tend to trust him.
Vitamin E: Vitamin E absorption is increased by some fat (26) but not really that much is needed (27). Vitamin E absorption is decreased by naringenin (27), which is found in grapefruit. Sesamin (found in sesame seeds) increases y-tocopherol absorption (28).
Zinc: Zinc absorption appears to be increased by meat protein and decreased by phytic acid, casein, soy protein, and iron (12). (perhaps add reference to zinc/copper balance?)
So...what else helps us poop out less of the vitamins, minerals, and other nutrients we eat?