Dairy

Dairy is a good source of calcium and vitamin D, but it’s difficult for many people to digest and tends to be allergenic. Some studies also link childhood dairy consumption with increased cancer risk. Active-cultured yogurt is the best option; it’s rich in probiotics and is more easily digestible. Reduced-fat versions contain less saturated fat, but they’re also lower in conjugated linoleic acid (CLA), which may improve heart health and increase lean muscle mass. Select organic varieties from grass-fed animals. Also try goat’s milk products; they contain less lactose (and often more calcium) than cow’s milk.
How much? No more than three servings a day. Vary calcium sources to include nondairy options, such as dark leafy greens and sesame seeds.

Seafood

In most cases, the benefits of eating fish outweigh the danger from toxins. To avoid PCBs, mercury, and other contaminants, choose wild seafood, stick with lower-toxin varieties such as shrimp, scallops, mussels, and sardines, and vary your choices. Download the Environmental Defense Fund’s seafood pocket guide (edf.org) for a list of safe picks.
How much? Two to four 4-ounce servings per week.

Eggs

They’re the most easily digested source of protein and they’re rich in brain-boosting choline. Eggs from pastured chickens have higher omega-3 and vitamin E levels, so ask your store to carry them. “Cage-free” and “free-range” designations mean little; look for the USDA Organic seal to avoid antibiotics and pesticides.
How much? One egg per day.

Red Meat and Poultry

Although higher in saturated fats than other proteins, these meats contain zinc, iron, and fatty acid CLA, which also exhibits cancer-protective and anti-obesity effects. Choose lean, skinless cuts such as chicken breast. Grass-fed bison and beef contain more beneficial omega-3s and CLA—and less saturated fat and calories—than grain-fed beef. Organic varieties are guaranteed free of antibiotics, hormones, nitrates, and other harmful additives. Bake, roast, broil, or grill meat safely; marinate first, use a lower flame, and remove any charred bits before eating.
How much? A 4-ounce serving no more than twice a week for red meat or pork, and two or three times a week for poultry.