Teen girls aren’t likely to be thinking about their risk for osteoporosis, but maybe they should be. Peak bone density is reached for most women in their early 20s, and what they are eating in their teen years has an enormous impact on the health of their bones later in life.
Calcium is an essential mineral found in dairy products, leafy green vegetables (spinach, mustard greens, collard greens), almonds, tofu, broccoli, green beans, tofu, asparagus, figs, and apricots. Calcium requirements vary based on need – and the need increases during times of growth, such as during teen growth spurts.
Calcium Requirements by Age (mg/day)
|Infants 0-6 months: 210|
|Infants 6-12 months: 270|
|Children 1-3 years: 500|
|Children 4-8 years: 800|
|Pre-teen 9-13 years: 1300 – 1500|
|Teen 14-18 years: 1300 – 1500|
|Adult 19-30 years: 1000|
|Adult 31-50 years: 1000|
|Adult 51 + years: 1200 – 1500|
|Teen pregnancy and lactation: 1300|
|Adult pregnancy and lactation: 1000|
Modified from Health Canada DRI Tables
A study published in the American Journal of Clinical Nutrition looked at the intake of calcium in the diet of over 350 teen girls and found that the majority of girls were consuming less than the recommended intake of 1300mg per day. The average calcium intake was 830mg/day – approximately 65% of the daily recommended intake. The study looked at the long term effects of supplementing teenage girls with calcium (supplementing with an additional 670mg/day to obtain a daily calcium intake of 1500mg/day) and found that giving teen girls calcium during their teen growth spurt produced higher bone mineral density, making bones bigger and stronger.
The researchers in this study expect that the benefits of calcium supplementation during the teen years will benefit these women into late adulthood, preventing osteoporosis. Several years of supplementation (ideally from 9-19 years of age) is necessary to have the maximum positive impact.
This study also found that taller girls benefit from higher levels of calcium (as they will have longer bones to support their height).
Supplementing with Calcium
The first step in meeting the calcium needs of teen girls is to include calcium rich foods in the diet. Below is a list of some of the highest food sources of calcium. Since dairy is a common source of calcium, special care must be taken by vegans to ensure they are getting enough calcium.
Calcium supplements should be used in teen girls to make sure optimal levels of calcium are achieved. Calcium should be taken with vitamin D to improve absorption of calcium.
Another way teen girls (and all women) can support healthy bones later in life is by engaging in weight-bearing physical activity several times per week.
Food Sources of Calcium
|Gruyere cheese (3oz)||860mg|
|Mozzarella cheese (3oz)||621mg|
|Cheddar cheese (3oz)||525mg|
|Turnip greens (1 cup, cooked)||492mg|
|Collard greens (1 cup, cooked)||357mg|
|Yogurt (1 cup)||345mg|
|Sesame seeds (1/4 cup)||340mg|
|Soy milk (fortified, 1 cup)||300mg|
|Cow milk (1 cup)||300mg|
|Spinach (1 cup, cooked)||245mg|
|Tofu (2/3 cup)||190mg|
|Broccoli (1 cup, cooked)||180mg|
|Blackstrap molasses (1 tbsp)||137mg|
|Almonds (1/4 cup)||92mg|
The teen years are a time of immense growth and development. Don’t forget that your bones are growing too. Support your bones, now and later in life, by consuming adequate calcium in your teens.
Health Canada: Dietary Reference Intakes Tables http://www.hc-sc.gc.ca/fn-an/nutrition/reference/table/index-eng.php
Velimir Matkovic, Prem K Goel, Nancy E Badenhop-Stevens, et. al. Calcium Supplementation and Bone Mineral Density in Females from Childhood to Young Adulthood: a Randomized Controlled Trial. American Journal of Clinical Nutrition. 2005; 81: 175-88.
Marz, Russell. Medical Nutrition from Marz. 2nd Ed. 1997.