- Dairy-food, calcium, magnesium, and vitamin D intake and endometriosis: a prospective cohort study. - (http://www.ncbi.nlm.nih.gov/pubmed/23380045)
- Choices for achieving adequate dietary calcium with a vegetarian diet. - (http://www.ncbi.nlm.nih.gov/pubmed/10479229)
- Intake of dairy products in relation to periodontitis in older Danish adults. - (http://www.ncbi.nlm.nih.gov/pubmed/23112910)
- Bioavailability of the calcium in fortified soy imitation milk, with some observations on method. - (http://www.ncbi.nlm.nih.gov/pubmed/10799379)
About
Most of the calcium in the body is found in bones. It is what gives your bones their strength and structure. A minuscule amount of calcium is dissolved in the blood, which plays an important role in the healthy functioning of the heart, muscles, blood and nerves. If you do not take in enough calcium, your body will pull calcium from the bones and pass it on to the bloodstream. And if this goes on for quite some time, your bones will become weak and you may develop osteoporosis.
A deficiency of calcium in the diet can weaken bones and raise the risk of osteoporosis, which affects one in five women over the age of fifty. Consuming enough calcium during one's lifetime may lower the risk of fractures and brittle bones in later life.
Other disorders associated with calcium deficiency are-
- High blood pressure
- Colon cancer
- Breast cancer
- Insulin resistance and obesity (metabolic syndrome)
- Premenstrual syndrome
- Lead poisoning
Daily Requirement of Calcium- Our bones achieve their highest density (Peak Bone Mass) by the time we are in our early twenties. Rapid bone loss occurs at menopause, so, at this time, women require more calcium. In older adults, calcium is absorbed less effectively from the intestine and more can be lost through the kidneys, so calcium intake needs to be maintained at a higher level.
The recommended daily value for adequate calcium-
- Adults and adolescents = 1000 mg
- Teens, women over 50 and men over 70 = 1300 mg
- Children below nine but more than one year old = 500 to 800 mg
You may be surprised by all the different foods that you can include in your diet to reach your daily recommended amount of calcium. Here are the top ones.
Milk- The food that tops the list of calcium-rich foods is milk, especially cow's milk and that is because a cup of fat-free or low-fat milk can give you 30 percent of the daily value of calcium requirement.
Although, findings are contradictory on whether milk is absolutely necessary for good bones, it is indisputable that in addition to calcium, milk contains potassium, magnesium, vitamin D, and vitamin A. And, your body needs vitamin D to absorb calcium. So, milk is sort of a complete calcium food.
Soy foods are lactose-free and a good substitute for milk or milk products if fortified with calcium.
Milk | Serving Size (Average) | Calcium (mg) |
Milk skimmed | Glass, 200 ml | 244 |
Milk whole | Glass, 200 ml | 236 |
Soy drink, calcium enriched | Glass, 200 ml | 178 |
Source: International Osteoporosis Foundation
Yogurt - A healthy alternative to milk is milk products, especially yogurt. The culturing process makes yogurt more digestible than milk. Moreover, the culturing of yogurt increases the absorption of calcium and B-vitamins. So much so, an 8-ounce (225g) serving of yogurt gets more calcium into your body than the same volume of milk can. Plain yogurt is not only rich in calcium but also contains around 10 to 14g of protein per 8 ounces (20 percent of the daily protein requirement for most individuals).
Yogurt | Serving Size (Average) | Calcium (mg) |
Yogurt, Low-fat, Fruit | 150 g | 210 |
Yogurt, Low-fat, plain | 150 g | 243 |
Source: International Osteoporosis Foundation
Use yogurt in soups, salads and desserts and increase the nutritive value and taste of the food.
Cheese- Cheese has low lactose content compared with other milk products and so it can be well tolerated by those who suffer from lactose intolerance. It promotes re-mineralization, that is, deposition of calcium and phosphorus in teeth, and also increases the strength of tooth enamel. Findings of a Danish study reveal that dairy calcium, particularly from milk and fermented products, may protect against periodontitis (gum disease). So, go ahead and enjoy your cheese! Here’s a tip - hard cheeses such as parmesan have a higher concentration of calcium than softer varieties such as ricotta.
Cheeses | Serving Size (Average) | Calcium (mg) |
Danish blue | 40 g | 195 |
Feta | 40 g | 144 |
Cheddar | 40 g | 296 |
Cheese spread | 30 g | 149 |
Cottage | 112 g | 142 |
Mozzarella, fresh | 56 g | 203 |
Parmesan, fresh | 30 g | 308 |
Source: International Osteoporosis Foundation
Vegetables and Leafy Greens- Milk and milk products are not the only sources of calcium, a lot of vegetables, especially, green leafy vegetables are rich source of calcium. For example, a three-fourth cup of collard greens has as much calcium as there is in one cup of cow’s milk.
Leafy green vegetables and broccoli are also great sources of vitamin K, another key nutrient for bone health.
Products | Serving Size | Estimated Calcium |
Collard greens, frozen | 8 oz | 360 mg |
Kale, frozen | 8 oz | 180 mg |
Soy Beans, green, boiled | 8 oz | 175 mg |
Bok Choy, cooked, boiled | 8 oz | 160 mg |
Broccoli, fresh, cooked | 8 oz | 60 mg |
Spinach, cooked | 1 cup | 240 mg |
Chard or Okra, cooked | 1 cup | 100 mg |
Turnip greens, raw | 1 cup | 80 mg |
Source: International Osteoporosis Foundation and UCSF Medical Center
However, some vegetables such as spinach, beets and carrots are high in oxalic acid content. And oxalates inhibit the absorption of calcium and reduce their bioavailability. So, the best way to consume these foods is by boiling them and tossing away the water.
Fruits, Nuts and Seeds- If you dislike milk and milk products or are intolerant to them, you will require more serves of other high calcium-containing foods. For example, eat more almonds, dried figs and dried apricots. Just 2 dried figs can give you 65mg of calcium. Here’s the table on calcium content in fruits (fresh, dried and juice). Nuts and seeds are rich in magnesium that helps your body absorb and retain calcium. Almonds and cashews are especially high in magnesium.
Products | Serving Size | Estimated Calcium |
Figs, dried, uncooked | 1 cup | 300 mg |
Kiwi, raw | 1 cup | 50 mg |
Orange Juice, calcium fortified | 8 oz (225 g) | 300 mg |
Orange Juice, from concentrate | 1 cup | 20 mg |
Oranges | 1 whole | 55 mg |
Similarly, calcium content in the nuts and seeds are as follows:
Products | Serving Size | Estimated Calcium |
Almonds, toasted unblanched | 1 oz (225 mg) | 80 mg |
Sesame seeds, whole roasted | 1 oz | 280 mg |
Sesame tahini | 1 oz (2 Tbsp) | 130 mg |
Sunflower seeds, dried | 1 oz | 50 mg |
Source: UCSF Medical Center
Seafood- Apart from calcium, seafood is a good source of iodine, vitamin K, B-vitamins, and magnesium and iron. Vitamin K and magnesium, both, help in absorption of calcium and increase its bioavailability.
The sea vegetable, kelp, can be used as a salt substitute or condiment in powder form. High in calcium and iodine, it acts as a natural tenderizer when added to beans and stews. Seaweeds such as kombu and wakame can be used in soups.
Since most of the calcium is found in the bones of the fish, eating fish along with the bones, as in canned fish, gives you most of the calcium.
Sea Food | Serving size | Estimated Calcium* |
Sardines, canned with bones | 3 oz | 325 mg |
Salmon, canned with bones | 3 oz | 180 mg |
Shrimp, canned | 3 oz | 125 mg |
Source: International Osteoporosis Foundation
Cereals and Bran- Whole grains and bran are high fiber, low-calorie foods that help lower your cholesterol and yes, help you lose weight, but they are not standouts in natural sources of calcium. That’s why cereal ready to eats are fortified with calcium and other minerals. An 8-ounce fortified cereal contains anywhere from 100mg to 1000mg of calcium.
Start your day with oats. Use milk instead of water, if you are not lactose intolerant, when making oatmeal or other hot breakfast cereals. This will give you the benefits of added calcium.
For example-
- 100g of KELLOGG’S ALL-BRAN Original contains 389 mg of calcium.
- 100g of Quaker Instant Oatmeal contains 866 mg of calcium.
- 100g of General Mills Total Corn Flakes contains 3333 mg of calcium.
A word of caution: Phytates in fiber interfere with calcium absorption. So you may not be absorbing all the calcium mentioned in your cereal breakfast box.
Soy and Soy Products- Soy does not contain a significant amount of calcium. The calcium in natural soybean is bound to the pulp of the bean which is indigestible by human beings. However, calcium is added to many soy-based products such as tofu and soy milk and this calcium can be easily absorbed.
Robert Heaney, the bone health expert from the Osteoporosis Research Center, Creighton University, Omaha, thinks otherwise. ‘Our findings show that calcium fortification of soy milk, at least by some producers, does not result in a calcium source comparable to cow milk in terms of either physical properties or absorbability,’ he said.
Heaney however ceded that calcium-set tofu is a concentrated source of bioavailable calcium for individuals who may not ingest enough dairy products to meet minimum daily requirements. ‘Calcium absorption from tofu was equivalent to that of milk,’ he said.
Minimize Foods that Deplete your Calcium Stores in the Body
Avoid the following foods:
- Soft drinks- they contain phosphoric acid that is known to increase calcium excretion in the urine
- Caffeine- for every 100mg of caffeine you take in, 6mg of calcium is leached out from your bones
- Alcohol- alcohol inhibits calcium absorption and disrupts your body’s calcium balance