We share seven simple ways to boost calcium intake and potentially reduce your blood pressure.
You may know that calcium is vital for strong bones and teeth. But did you know it plays a role in blood pressure control?
Researchers don’t completely understand how calcium regulates blood pressure, but they know it involves a system of hormones and that a low calcium diet may increase blood pressure.
This article discusses how to boost calcium intake to reduce blood pressure.
Before we dive in, let’s cover some basics.
What is Calcium?
Calcium is the most abundant mineral in the body. It makes up 1.5-2% of total body weight, with over 99% found in the bones (Institute of Medicine, 2011). The body needs it for a variety of functions, including:
- Building and maintaining strong bones and teeth
- Transmitting signals from the brain to the body
- Helping muscles move
- Regulating heartbeat
- Blood clotting
- Helping enzymes carry out their functions
What is high blood pressure?
High blood pressure, also known as hypertension, is when the force of blood pushing against the walls of blood vessels is consistently too high, making the heart work harder to pump blood (Shahoud, 2022).
In the United States, high blood pressure is diagnosed when readings are consistently 130/80 mmHg or higher over several weeks, and in the UK and Nigeria, when they are over 140/90 mmHg (Whelton et al., 2022; Jones et al., 2020; Kadiri et al., 2020). High blood pressure is also diagnosed if just one of the numbers is higher than normal, i.e., if the top number (systolic) is over 139 mmHg or the bottom (diastolic) is over 89 mmHg.
How calcium contributes to blood pressure control?
Calcium intake may control blood pressure in a process involving the parathyroid gland, vitamin D and the renin-angiotensin-aldosterone system (RAAS) – a network of proteins that regulate blood pressure (Villa-Etchegoyen et al., 2019).
Low calcium intake activates the RAAS system, increases vitamin D production and causes the parathyroid gland to make more parathyroid hormone. These changes increase the amount of calcium in muscle cells, causing blood vessels to narrow and blood pressure to rise (Villa-Etchegoygen et al., 2019). Angiotensin II, a protein in the RAAS system, and parathyroid hormone can also activate the adrenal gland to release a protein called aldosterone. This protein makes the kidneys reabsorb water and sodium, leading to a rise in blood pressure (Maniero e al., 2011).
Many observational studies have found a link between a higher calcium intake and a reduced risk of high blood pressure. For example, a Cochrane review analysed data from 20 trials and found that higher calcium intakes modestly reduced systolic and diastolic blood pressure by 1.37 mmHg and 1.45 mmHg, respectively (Cormick et al., 2022).
The effect of calcium on blood pressure was more evident at higher doses; Systolic blood pressure was reduced by 1.05 mmHg in participants taking 1000-1500 mg of calcium daily and by 2.79 mmHg in those taking 1500 mg or more daily. However, not all studies support this finding. A study in 2021 assessed data from 26,778 adults collected during the National Health and Nutrition Examination Survey (NHANES) between 2007-2018. The study found a 45% higher incidence of hypertension in participants with the highest calcium levels than those with the lowest (Hua et al., 2021).
How much calcium should you eat daily?
The recommended daily intake of calcium for adults in the United Kingdom aged 19-64 is 700 mg daily (Public Health England, 2016). It is 1,000 mg daily for American adults aged 19-50 and 1,200 for women aged 51-70 (Institute of Medicine, 2011).
What are the best sources of calcium?
Calcium is rich in kelp, seaweeds, dairy products such as milk, yoghurt and cheese, and green leafy vegetables such as collard greens, kale and turnip greens. Canned fish with bones, such as sardines and salmon, are also good sources, as are nuts and seeds.
| Calcium Content of Selected Foods in milligrams per 100g serving | |
| Food | Calcium content |
| Kelp Cheddar cheese *Moringa leaves Sardines, canned *Amaranth leaves (Efo/callaloo) *Jute (Ewedu/Bush okra/Lalo) *African eggplant leaves (Efo Igbo) *Baobab (Kuka) Pink salmon, canned Collard greens Kale Turnip greens Almonds Parsley Brazil nuts Tofu Sunflower seeds Yoghurt Sesame seeds Broccoli Soybeans, cooked Pecans Peanuts Green beans Pumpkin seeds | 1093 750 434 382 380 360 332 313 283 250 249 246 234 203 186 128 120 120 110 103 73 73 69 56 51 |
7 ways to boost calcium intake
Add chopped almonds, Brazil nuts or pecans to oatmeal or other cereal at breakfast
Eat a small handful of almonds for a midday snack
Add a side of sauteed amaranth to steamed rice and grilled salmon
Eat a small pot of yoghurt with berries and chopped pecans or sunflower seeds
Top toast with grilled sardines and sauteed kale
Choose wholegrain bread with seeds and top with peanut butter or another nut butter spread
Make a stir-fry with leafy green vegetables such as bok choi, broccoli and kale, tofu and cashews.
Should you take calcium supplements?
Getting calcium from your diet is the best option, especially as some studies show that calcium supplements may increase the risk of heart disease (Yang et al., 2020). That said, check with your doctor to find out if supplements are an option.
There are two types of calcium supplements – calcium carbonate and calcium citrate. Calcium carbonate is less expensive and readily available. The body absorbs it best when taken with food. Calcium citrate can be taken on an empty or full stomach. It works well for older adults and people with low stomach acid from taking acid blockers.
In summary, increasing your calcium intake can modestly reduce your blood pressure and your risk of developing high blood pressure. However, it is best to get calcium from food because you’re less likely to take too much, which increases your risk of adverse effects. Always speak to your physician or registered nutritionist/dietitian before taking supplements.
REFERENCES
- Institute of Medicine (US) Committee to Review Dietary Reference Intakes for Vitamin D and Calcium (2011). Overview of Calcium. Available from: https://www.ncbi.nlm.nih.gov/books/NBK56060/. Accessed 07 February 2023
- Shahoud J.S. (2022) Physiology, arterial pressure regulation. Available from: https://www.ncbi.nlm.nih.gov/books/NBK538509/. Accessed: 22 December 2022.
- Whelton, P.K., Carey, R.M., Mancia, G., Kreutz, R., Bundy, J., & Williams, B. (2022) Harmonization of the American College of Cardiology/American Heart Association and European Society of Cardiology/European Society of Hypertension Blood Pressure/Hypertension Guidelines: Comparisons, Reflections and Recommendations. Circulation, 146: 868-877.
- Jones, N.R., McCrmack, T., Constanti, M., & McManus, R.J. (2020) Diagnosis and management of hypertension in adults: NICE guideline update 2019. British Journal of General Practice; 70 (691): 90-91.
- Kadiri, S., Arogundade, F., Arije, A., Omotoso, A., Onwubere, B., Aderibigbe, A., Isah, A., Mbakwem, A., Salako, B., Isezuo, S., Ogun, S., Sani, M., Ulasi, F., Familoni, O., Ogbera, A., Ogah, O., Ademola, A., Opadeyi, A., Asinobi, A., for The Nigerian Hypertension Society Guidelines Committee. (2020) Guidelines for the management of hypertension in Nigeria 2020. Tropical Journal of Nephrology, 15(1): 65-84.
- Villa-Etchegoyen, C., Lombarte, M., Matamoros, N., Belizan, J.M., & Cormick, G. (2019) Mechanisms involved in the relationship between low calcium intake and high blood pressure. Nutrients, 11(5): 1112.
- Maniero, C., Fassina, A., Guzzardo, V., Lenzini, L., Amadori, G., Pelizzo, M.R. et al. (2011). Primary hyperparathyroidism with concurrent primary aldosteronism. Hypertension; 58: 341-6.
- Cormick, G., Ciapponi, A., Cafferata, M. L., Cormick, M. S., & Belizán, J. M. (2022). Calcium supplementation for prevention of primary hypertension. The Cochrane Database of Systematic Reviews, 2022(1). https://doi.org/10.1002/14651858.CD010037.pub4
- Hua, Y., Liu, H., Sun, J., Kong, X., Sun, W., & Xiong, Y. (2021). Association Between Serum Calcium and the Prevalence of Hypertension Among US Adults. Frontiers in Cardiovascular Medicine, 8. https://doi.org/10.3389/fcvm.2021.719165.
- Public Health England (2016). Government recommendations for energy and nutrients for males and females aged 1-18 years and 19+ years. Available: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/618167/government_dietary_recommendations.pdf Accessed: 07 February 2023.
- National Institute of Health. Calcium – fact sheet for health professionals (2022). Available: https://ods.od.nih.gov/factsheets/Calcium-HealthProfessional/ Accessed: 07 February 2023.
- Yang, C., Shi, X., Xia, H., Yang, X., Liu, H., Pan, D., and Sun, G. (2020) The evidence and controversy between dietary calcium intake and calcium supplementation and the risk of cardiovascular disease: a systematic review and meta-analysis of cohort studies and randomized controlled trials. Journal of the American College of Nutrition, 39(4): 352-370.
DISCLAIMER: Not a substitute for medical advice – All content is for informational purposes only and is not intended to provide medical or nutrition advice or to take the place of medical/nutrition advice or treatment from your doctor or health professional. Since each person’s health conditions are very specific, viewers of this content are advised to consult their doctors or qualified health professionals regarding specific health questions. All content, including text, graphics, images, and information in this post/video, is for general information only and does not replace a consultation with your doctor/health professional.
