Get calcium and vitamin D by growing and eating vegetables and fruit

Sarah Rautio<rautio@msu.edu>, Michigan State University Extension - May 21, 2018

Vegetables and fruit can provide calcium and gardening offers sunlight to help your body absorb it.

Swiss Chard is a vegetable that contains calcium. Its seeds can be planted in late spring. | Photo by Sarah Rautio

Calcium is a mineral that the body uses in small amounts to maintain healthy blood vessels, muscles, nerves and the functions of hormones. 99 percent of the body’s calcium is stored in bones and teeth. Stored calcium needs to be supplemented with dietary intake of calcium in the form of food or supplements so that new bone cells can be created to replace old ones, for calcium production, and body strength and support.

The Recommended Dietary Allowances (RDA) of calcium range from 200 to 1,300 mg/day, depending on a person's age. Less is needed at younger ages and more is recommended as we age. This is mostly due to the body’s changing ability to regenerate new bone cells as we progress through life. In general, a person over the age of nine years old should consume approximately 10000 mg of calcium daily. One way to think about reaching this need might be to consume 3 cups of milk a day – as 1 cup provides a little over 290 mg/cup.

Vegetables and fruit can provide calcium

In addition to milk, some vegetables contain enough calcium to meet a portion of the body’s daily calcium needs. This is especially helpful for those who choose diets rich in vegetables and/or avoid dairy products. Although a good source, vegetables may not provide the total daily recommended amounts of calcium. Soy-based products, bread, fish with bones and supplements can be used to help meet the daily amount, if needed. To determine if you are getting enough calcium on a daily basis, try the Calcium Calculator put out by the Dairy Council of California.

There are numerous vegetables and fruits that contain calcium-some more than others. Many calcium-rich vegetables can be grown in Michigan. Some calcium-rich fruit (most notably rhubarb) can be grown in Michigan; however, tropical fruit sources of calcium can still be purchased from markets.

Cooking vegetables can increase the amount of calcium they can provide

Cooking vegetables usually always increases the amount of calcium available in the vegetable for the body to absorb, and this difference can be big. For example, cooked spinach has 245 mg/cup of calcium, while raw spinach only has 30mg/cup! Keep in mind, raw vegetables can be higher in other nutrients than cooked versions (e.g., raw spinach has three times as much vitamin C than when that same amount is cooked). Eating a varied diet that includes both raw and cooked vegetables is a good way to ensure intake of needed nutrients.

Vegetable and fruit calcium content per cup (from highest to lowest calcium content) – all those listed can be grown in Michigan.

Vegetables

Cooked Greens:
- Collards (268mg)
- Spinach (245mg)
- Turnip greens (197mg)
- Curly Scotch kale (172mg)
- Beet greens (164mg)
- Bok choy (158mg)
Raw Greens:
- Curly Scotch kale (137mg)
- Turnip greens (105mg)
- Collards (85mg)
Cooked Swiss Chard (102mg)
Broccoli Raab (100mg)
Kales besides Scotch (94mg)
Cooked okra (123mg)
Cooked squash (80-90mg)
Sweet potatoes (77mg)
Cooked podded peas (94mg)
Cooked parsley (83mg)

Fruit

Rhubarb (348mg)
Mulberries (55mg)
Blackberries (42mg)

Calcium content of fruits and fruit juices that cannot be grown in Michigan include:

Fortified orange juice (349mg/cup)
Kumquats (94mg/eight)
Prickly pears (83mg/cup)
Tangerines/oranges (72mg/cup)
Kiwi (61mg/cup)
Guava/papaya/passion fruit (all around 30mg/cup)

Growing sources of calcium and absorbing vitamin D go hand in hand

There are many factors that influence the bioavailability of nutrients, especially in plant-based foods. One important consideration when consuming calcium is that the body also needs vitamin D in order to effectively absorb calcium into the body. This is because the protein that picks up the calcium in the intestine needs vitamin D. Milk products and some calcium supplements also contain vitamin D.

Did you know that vitamin D is also absorbed through the skin from sunlight? This means that people who grow and care for any of the above fruit and vegetables are also obtaining the vitamin D they need while gardening! This calcium-rich food and sunlight combo is just one of the many health benefits of gardening. Gardening has numerous health benefits, from supplying healthy vegetables and fruits to getting variable forms of physical exercise, improved mental well-being, and better social and emotional health. For more information on growing your own fruit and vegetables, explore MSU Extension’s Smart Gardening Resources.

For more information on calcium, visit the USDA’s online Food and Nutrition Information Center.

Michigan State University Extension has a range of nutrition programs and resources to help you eat a variety of nutritious foods including fruits and vegetables.

This article was published by Michigan State University Extension. For more information, visit https://extension.msu.edu. To have a digest of information delivered straight to your email inbox, visit https://extension.msu.edu/newsletters. To contact an expert in your area, visit https://extension.msu.edu/experts, or call 888-MSUE4MI (888-678-3464).