Calcium is the most abundant mineral in the body. This nutrient helps you maintain strong bones and teeth, powers your muscles, and supports nerve and hormone function. Calcium is an essential mineral, meaning your body doesn’t naturally produce it on its own. Therefore, including an adequate amount of calcium in your diet is important for optimal health.
Dairy products are rich sources of calcium, but you can also find it in plant-based foods like soy products, leafy greens, nuts, and seeds.
Why Do We Need Calcium?
Calcium is used by your body in a variety of ways. For example:
- More than 99% of the calcium in your body is found in your bones and teeth, where it provides structure and strength.
- Calcium supports effective nerve signaling by helping to send messages between the cells of the nervous system, which includes your brain and spinal cord.
- The blood clotting process requires calcium.
- Your muscles can’t contract without high enough calcium levels, making it essential for movement.3
- Adequate dietary calcium intake may help reduce the risk of cancer, especially colorectal cancer, though research is needed. Colorectal cancer is a cancer of the large, muscular tube known as the colon, or cancer of the rectum, the lowest part of your digestive tract.
How Much Calcium Do We Need?
As of 2016, the U.S. Food and Drug Administration set the recommended Daily Value (DV) of calcium at 1,300 milligrams (mg) for ages 4 and older.
Daily Value
Every food product has a nutrition label stating the amount of calories, fats, and other nutrients per serving. The U.S. Food and Drug Administration (FDA) selects a value for each nutrient based on the needs of the general population.
These Daily Values (DVs) are listed as percentages in the right column of food labels. The percentages can help you determine how much of a certain nutrient one serving of a food provides compared to the suggested daily intake.
Recommended Dietary Allowances (RDAs) are developed by the Food and Nutrition Board at the Institute of Medicine of the National Academies. RDAs are designed to meet the nutritional requirements of most people. They vary depending on a person’s age and sex. These are the RDAs for calcium:
- 0-6 months: 200 mg
- 7-12 months: 260 mg
- 1-3 years: 700 mg
- 4-8 years: 1000 mg
- 9-13 years: 1,300 mg
- 14-18 years: 1,300 mg
- 19-50 years: 1,000 mg
- Men aged 51-70 years: 1,000 mg
- Women aged 51-70 years: 1,200 mg
- 71+ years: 1,200 mg
What Foods Are Good Sources of Calcium?
While dairy products like milk and yogurt are great sources of calcium, fish, plant-based foods, and fortified products can also contain this essential mineral.
Dairy
Dairy products are among the richest sources of calcium. They also contain high-quality protein, which builds and preserves muscle. Foods like yogurt and kefir offer up gut-friendly probiotics, and milk is often fortified with vitamin D. This means that manufacturers add vitamin D into the milk during the production process. Dairy also contains nutrients like potassium, zinc, magnesium, and phosphorus.7
Here’s the calcium content of popular dairy products:8
- Whole milk: 300 mg per cup, or about 23% of the DV
- Plain, whole milk Greek yogurt: 260 mg per cup, or about 20% of the DV
- Cheddar cheese: 120 mg per slice, or about 11% of the DV
Soy
Soy-based ingredients like tofu are often prepared with calcium sulfate, a salt that helps maintain the plant protein’s texture and structure. Tofu products made with this salt are good sources of calcium.2
It’s also not uncommon for soy milk to be fortified with both calcium and vitamin D so that consumers don’t miss out on these important nutrients if they don’t eat dairy. Calcium content varies depending on the brand.9
Products like the following can help you meet your daily calcium requirements:8
- Tofu made with calcium sulfate: 434 mg per one-half cup, or about 33% of the DV
- Soy milk fortified with calcium: 300 mg per cup, or about 18% of the DV
- Soybeans (boiled): 261 mg per cup, or about 20% of the DV.
Canned Fish
Canned fish, like salmon and sardines, are great sources of calcium. Unlike tuna, these fish are canned with their bones, which contain both calcium and vitamin D. The bones are so soft and fine that they’re easy (and safe) to chew.
Eating fatty fish three times a week is a great way to include omega-3 fatty acids into your diet. Omega-3 fatty acids help reduce inflammation in your body.10
Try incorporating one of the options below for an affordable dose of calcium:8
- Canned sardines: 286 mg per 2.65-oz can, or about 22% of the DV
- Canned sockeye salmon: 197 mg per 3 oz, or about 15% of the DV
- Canned crab: 114 mg per 6.5-oz can, or about 9% of the DV.
Leafy Greens
Leafy greens are full of nutrients, including vitamins A, C, E, and K, as well as iron and fiber. They’re also a dairy-free source of calcium.11 Here’s the calcium content of some leafy greens:8
- Collard greens: 327 mg per cooked cup, or about 25% of the DV
- Spinach: 141 mg per cooked cup, or about 11% of the DV
- Kale: 177 mg per cooked cup, or about 14% of the DV.
Nuts and Seeds
Some nuts and seeds also bring calcium to the table. Almonds and sesame seeds—including almond butter and tahini, the paste made from sesame seeds—both deliver the mineral, along with antioxidants like vitamin E.12 Antioxidants are substances that prevent or delay cell damage caused by compounds called free radicals.
The following nuts and seeds are particularly rich in calcium:8
- Almonds: 96 mg per one-quarter cup, or about 7% of the DV
- Tahini: 127 mg per 2 tablespoons, or about 10% of the DV
- Chia seeds: 90 mg per tablespoon, or about 7% of the DV.
Fortified Products
A few countries have experimented with fortifying commonly consumed foods to help increase population-level calcium intake. For example, wheat flour fortification is mandatory in the United Kingdom. The idea is that this process can help reduce the prevalence of conditions correlated with low calcium intake, including rickets in children and preeclampsia in pregnant women.13
In the United States, calcium is often added to juices and foods like breakfast cereals, as well as dairy and plant-based milk. Common fortified foods include:
- Fortified cold breakfast cereal: Up to 150 mg per cup, or about 12% of the DV
- Fortified orange juice: 300 mg per cup, or about 23% of the DV
- Fortified wheat flour: 67 mg per cup, or about 5% of the DV.
What Happens When You Don’t Get Enough Calcium?
Calcium deficiency can lead to symptoms like muscle weakness and spasms, as well as numbness and tingling. More severe cases may contribute to mood disturbances, compromised vision, and cardiovascular disease (CVD), which affects the heart or blood vessels.
Chronic, inadequate calcium intake can also lead to low bone mineral density. This is seen in conditions such as rickets, which softens and weakens the bones, often seen in children. It’s also seen in osteopenia and osteoporosis, conditions that thin and weaken bones in adults.
Low blood calcium levels in pregnant women have been associated with a greater risk of preeclampsia, a serious blood pressure condition. This is particularly seen in populations with low calcium intake and for women at a higher risk of preeclampsia.
Risk Factors
Many people, of all ages, are calcium deficient. In the U.S., about 60% of adults assigned female at birth and 30% of people assigned male at birth do not consume enough calcium. Risk factors for a calcium deficiency include:
- Adolescence: Calcium is critical for bone growth, which is why it’s important for children and adolescents to consume enough calcium. Eating disorders and other changes in eating habits can decrease the amount of calcium consumed by teenagers.
- Female athlete triad syndrome: This condition is characterized by disordered eating, osteoporosis, and amenorrhea, the absence of a period for at least three months. It’s often caused by stress, weight loss, or frequent exercise.
- A milk allergy or lactose intolerance: Not eating dairy requires finding other sources of calcium, as well as making sure you’re getting enough to meet your daily needs.
- Menopause: The body has more difficulty absorbing and maintaining calcium after menopause.
- Older age: Bones start losing calcium after about the age of 30, and medications can interact with calcium absorption.
Other Considerations
Vitamin D is a key regulator of calcium levels in the body. It’s a fat-soluble vitamin, which means the digestive tract absorbs the vitamin with dietary fats to send into the bloodstream. Vitamin D is required for absorbing adequate amounts of calcium, which is why low levels of this vitamin can increase your risk of osteoporosis.2 You can help protect your bones by getting adequate vitamin D through dietary sources, safe sunlight exposure, and possibly a supplement, if needed.
Talk to a healthcare provider or a registered dietitian (RD) about trying a calcium supplement if you’re worried about meeting your daily needs. It’s important to determine the correct dosage, as consuming too much calcium from supplements may increase your risk of conditions like kidney stones and cardiovascular disease over time. An RD has completed standardized training in how the human body works and the understanding of nutrition science.218
Dietary supplements are minimally regulated by the FDA and may or may not be suitable for you. The effects of supplements vary from person to person and depend on many variables, including type, dosage, frequency of use, and interactions with current medications. Please speak with your healthcare provider or pharmacist before starting any supplements.
A Quick Review
Calcium is a critical nutrient for optimal bone health, as well as proper muscle and nerve function. Maintaining adequate vitamin D levels is also essential for maintaining adequate calcium stores in your body.
You can meet your daily calcium needs by including calcium-rich foods and drinks in your diet. Reach out to a healthcare provider or a registered dietitian if you’re struggling to consume enough calcium or worried you may have a calcium deficiency. They can help ensure you’re meeting your needs.
Credit: Anthea Levi, health.com