Nutrition by age: A guide to healthy eating and meeting daily needs

Advice for a healthy diet is the same for men and women: Eat more fruit, vegetables, whole grains, legumes and nuts. Limit sodium, sugar and saturated fat. But when it comes to the dirty details – the individual nutrients – there are some notable differences between the sexes, largely due to differences in male and female hormones.

Blood loss through menstruation increases a woman's daily need for iron. Thanks to testosterone, men have more muscle mass and higher metabolic rates than women, driving up requirements for protein, many B vitamins and zinc.

Nutrient requirements change as we get older, in large part because of changing hormone levels. Aging can also affect whether you're better off getting a certain nutrient from a supplement rather than food.

Tailoring food intake to match nutritional needs is important to maintain immune function, prevent bone and muscle loss, preserve eyesight and protect our cells from free-radical damage.

The following guide will help you – whether you're male or female – eat healthfully and meet daily needs for key nutrients across the decades.

In your 20s: Focus on calcium, folate, iron

Men and women continue to build bone into the mid-20s, although not as readily as when younger. Meeting daily calcium requirements is important to help bones reach their peak strength. Doing so can help protect against osteoporosis and fractures later in life.

Men and women need 1,000 mg of calcium each day. One milk serving (e.g., 1 cup milk, 3/4 cup plain yogurt, 1 1/2 ounces hard cheese) supplies about 300 milligrams of calcium. Fortified non-dairy beverages such as soy, rice and almond milks contain 300 to 330 mg of calcium per one cup. So do calcium-fortified juices.

Other good sources include canned salmon (3 ounces = 212 mg), legumes, firm tofu, almonds, tahini and cooked green vegetables such as spinach, collard greens, rapini and bok choy.

Folate is vital to making and repairing DNA, the genetic material of cells. While both sexes require 400 micrograms (0.4 mg) daily, women who plan to get pregnant must pay extra attention to the B vitamin to guard against neural-tube defects, birth defects that affect the brain and spinal cord.

Folate-packed foods include cooked spinach (1/2 c = 130 mcg), broccoli (1/2 c = 84), lentils (1/2 c = 189), black beans (1/2 c = 135) and avocado (1/2 medium-sized = 113). Women of childbearing age should also take a multivitamin that supplies 0.4 to 1 mg of folic acid (the synthetic form of folate).

Iron supports metabolism, transfers oxygen to muscles, aids mental concentration and is used to make hormones and connective tissue. Men need 8 mg of the mineral each day while women need 18 mg to offset iron losses from menstruation.

Oysters, red meat, enriched breakfast cereals, soybeans, lentils, chickpeas, cooked spinach, prunes and raisins are good sources.

In your 30s: Focus on calories and magnesium

In the 30s, the onset of age-related muscle loss slows down our body's metabolism and calorie requirements begin to decline. If you keep your same eating pattern in your 30s (and 40s) as you did in your 20s, you'll likely gain weight. (Strength training and eating enough protein can help mitigate muscle loss.)

For every year after 30, men require 10 fewer calories a day and women need 7 fewer. In other words, by age 40, men should be eating 100 fewer calories each day than at 30; women should cut 70 calories from their daily diet at the age of 40.

Trim calories from refined (white) starchy foods, sweets and sugars added to beverages and foods. Continue to emphasize foods rich in calcium, folate and iron.

Men and women should also focus on magnesium, a mineral that helps generate energy for the body, regulate blood pressure and blood sugar and maintain strong bones. At the age of 31, daily requirements increase for both men (420 mg) and women (320 mg).

To increase your intake, reach for halibut (3 oz = 90 mg), almonds (24 nuts = 80), cooked Swiss chard (1/2 c = 80), cooked spinach (1/2 c = 78), cashews (18 nuts = 75), plain yogurt (1 c = 45) and raw wheat bran (2 tbsp = 45).

In your 40s: Focus on antioxidants

While vitamin and mineral requirements remain unchanged in the 40s, both sexes should focus on making nutrient-dense food choices, not only to meet daily requirements but also to pave the way for the next few decades.

Include foods high in vitamins C and E, antioxidants that fend off harmful free radicals. Free-radical damage is thought to contribute to aging and many chronic diseases.

Excellent sources of vitamin C include red and green pepper, citrus fruit, kiwi, broccoli, Brussels sprouts, strawberries and tomato juice. Vitamin E is plentiful in wheat-germ oil, sunflower seeds, almonds, sunflower oil, hazelnuts and peanut butter.

Other dietary antioxidants include beta-carotene (e.g., carrots, sweet potato, apricots, green vegetables) and selenium (e.g., Brazil nuts, tuna, shrimp, turkey).

Unlike supplements, whole foods provide vitamins and minerals along with fibre and hundreds of phytochemicals, which work in concert to protect health.

In your 50s and beyond: Focus on calcium, vitamin D, B12

At the age of 51, women need 1,200 mg of calcium each day to help counter the rapid bone loss that occurs at menopause. Calcium requirements don't increase for men until the age of 71, when bone loss and fracture risk rise significantly. With age, men and women have a reduced capacity to produce vitamin D through sun exposure. The official recommended dietary allowance for vitamin D increases from 600 IU (international units) to 800 IU at the age of 70. However, many experts recommend adults older than 50 supplement with 1,000 to 2,000 IU each day to maintain sufficient stores.

Vitamin B12, needed to make red blood cells, nerves and DNA, should also be supplemented after 50; a multivitamin will do the trick. Many older adults do not produce enough hydrochloric acid in their stomach to absorb the vitamin from foods.

Leslie Beck, a registered dietitian, is based at the Medisys clinic in Toronto. She is a regular contributor to CTV News Channel.