THE DOC AND CHEF SHOW EP. 16: PLANTS HAVE CALCIUM? // SUPPORTING SCIENCE AND THE RECIPE
WHY IS CALCIUM IMPORTANT?
Calcium plays several crucial roles in the body, making it an essential mineral for overall health. Here are some of the key functions of calcium:[1]
1. Bone Health: Calcium is vital for the development, growth, and maintenance of strong bones and teeth. About 99% of the body's calcium is stored in bones and teeth, where it provides structural support.
2. Muscle Function: Calcium is essential for muscle contractions, including the beating of the heart. It enables the muscles to contract by facilitating the binding of proteins within muscle cells.
3. Nerve Transmission: Calcium is necessary for the transmission of nerve impulses throughout the nervous system. It plays a role in the release of neurotransmitters, which are chemicals that transmit signals from one neuron to another.
4. Blood Clotting: Calcium is a key component in the process of blood clotting. It helps in the conversion of prothrombin to thrombin, an essential step in blood clot formation.
5. Vascular and Heart Function: Calcium is important for maintaining normal blood pressure and heart function. It helps in the relaxation and contraction of blood vessels, which is essential for normal blood pressure regulation.
6. Hormonal Secretion and Enzyme Function: Calcium assists in the secretion of various hormones and the functioning of enzymes throughout the body. These hormones and enzymes play a role in various bodily functions, from digestion to energy metabolism.
7. Cellular Function: Calcium plays a role in various cellular functions such as cell division, cell signaling, and maintaining the stability of cell membranes.
Adequate calcium intake is essential for maintaining these functions.
HOW MUCH CALCIUM DO WE NEED?
The amount of calcium an individual needs varies depending on age, gender, and life stage. The Recommended Dietary Allowances (RDAs) for calcium, as outlined by the National Institutes of Health (NIH), provide general guidelines:[2]
● Infants:
- 0-6 months: 200 milligrams (mg) per day
- 7-12 months: 260 mg per day
● Children:
- 1-3 years: 700 mg per day
- 4-8 years: 1,000 mg per day
- 9-18 years: 1,300 mg per day
● Adults:
- 19-50 years: 1,000 mg per day for both men and women
- Men 51-70 years: 1,000 mg per day
- Women 51-70 years: 1,200 mg per day
- 71 years and older: 1,200 mg per day for both men and women
● Pregnant and Lactating Women:
- 18 years and younger: 1,300 mg per day
- 19 years and older: 1,000 mg per day
It's important to note that excessive calcium intake can lead to adverse health effects, such as kidney stones and can interfere with the absorption of other minerals like iron and zinc. Therefore, while ensuring adequate calcium intake is important, it's also crucial not to exceed the upper intake levels. For most adults, the upper intake level is set at 2,000 to 2,500 mg per day.
WHAT FOODS ARE HIGH IN CALCIUM?
Dietary sources of calcium are varied and can cater to different dietary preferences and restrictions. Here are some common sources:[3]
1. Dairy Products: This is the most well-known group. It includes milk, cheese, yogurt, and kefir. Dairy products are among the richest sources of calcium.
2. Leafy Green Vegetables: Certain vegetables, especially dark, leafy greens like collard greens, turnip greens, kale, and bok choy, have significant calcium content. Spinach also contains calcium, but it's less available for absorption due to its high oxalate content.
3. Fortified Foods: Many foods are fortified with calcium, including plant-based milk alternatives (such as almond, soy, and rice milk), some cereals, orange juice, and tofu made with calcium sulfate.
4. Nuts and Seeds: Almonds, sesame seeds, chia seeds, and tahini (sesame seed paste) contain calcium.
5. Legumes: Beans, particularly white beans, chickpeas, and black-eyed peas, have notable amounts of calcium. Lentils also contain some calcium.
6. Dried Fruits: Some dried fruits like figs and apricots contain calcium.
7. Certain Grains: Amaranth and quinoa are grains that provide some calcium.
ARE THERE HEALTH RISKS ASSOCIATED WITH DAIRY CONSUMPTION?
Although dairy products contain essential nutrients like calcium, vitamin D, protein, and potassium, there can be health risks or concerns associated with dairy consumption. Here are a few of the potential issues:
1. Lactose Intolerance: This is a common condition where the body lacks enough of the enzyme lactase, which is needed to digest lactose, the sugar found in milk. Consuming dairy products can lead to symptoms like bloating, gas, and diarrhea in lactose-intolerant individuals.[4]
2. Allergy to Milk Proteins: Some people, especially children, can have an allergic reaction to the proteins in cow's milk. Symptoms can range from mild (such as hives or a rash) to severe (such as anaphylaxis).[5]
3. High Saturated Fat Content: Full-fat dairy products contain high levels of saturated fats, which can contribute to increased levels of LDL cholesterol and a heightened risk of heart disease when consumed in excess.
[6]4. Hormones and Antibiotics: Concerns are sometimes raised about the presence of hormones and antibiotics in milk. These concerns largely relate to farming practices and regulations vary by country. [7]
5. Acne and Skin Conditions: Some studies suggest a link between consuming dairy products and acne development, although the evidence is not conclusive and more research is needed.[8]
6. Ovarian and Prostate Cancer: Some research suggests a potential link between high dairy consumption and an increased risk of certain cancers like ovarian and prostate cancer. However, these findings are not definitive, and more research is needed to understand these relationships.[9]
7. Bone Health Concerns: While dairy is a good source of calcium, there's ongoing debate about its effects on bone health. Some studies suggest that very high milk intake may not necessarily prevent osteoporotic fractures and might be linked to certain negative health outcomes, but these findings are not conclusive.[10]
ARE THERE HEALTH RISKS ASSOCIATED WITH TAKING CALCIUM SUPPLEMENTS?
There are potential risks associated with taking calcium supplements, especially when taken in high doses or without medical supervision. Here are some of the key concerns:[11]
1. Kidney Stones: High levels of calcium, particularly from supplements, can increase the risk of developing kidney stones, especially in individuals with a history of kidney stones.
2. Hypercalcemia: This is a condition characterized by abnormally high levels of calcium in the blood. It can cause various symptoms such as nausea, vomiting, confusion, and in severe cases, it can be life-threatening.
3. Cardiovascular Disease: Some studies have suggested that excessive calcium intake from supplements might be associated with an increased risk of heart disease. However, the evidence is mixed and more research is needed in this area.
4. Interference with Absorption of Other Minerals: High levels of calcium can interfere with the body's ability to absorb other minerals, such as iron, zinc, and magnesium.
5. Digestive Symptoms: Some people may experience gastrointestinal side effects like constipation, bloating, and gas when taking calcium supplements.
6. Interactions with Medications: Calcium supplements can interact with various medications, including bisphosphonates (used to treat osteoporosis), antibiotics in the fluoroquinolone and tetracycline families, blood pressure medications, and certain diuretics.
7. Exceeding the Upper Intake Level: It's important not to exceed the upper safe limits of calcium intake (usually 2,000-2,500 mg per day for adults, depending on age and sex) as it can lead to negative health outcomes.
For most people, dietary sources of calcium are sufficient and preferable to supplements. Supplements should be considered when dietary intake is insufficient. However, they should be used judiciously and ideally under the guidance of a healthcare provider. It's also important to balance calcium intake with adequate vitamin D, as vitamin D is necessary for the body to absorb and utilize calcium effectively.
SUMMARY
Calcium plays a crucial role in building and maintaining strong bones and teeth, thereby reducing the risk of osteoporosis, especially in older adults and postmenopausal women. Calcium also supports muscle function, nerve signaling, and heart health. However, excessive intake of calcium, particularly from supplements, can pose risks. It may lead to hypercalcemia, a condition characterized by elevated calcium levels in the blood, which can cause kidney stones, constipation, and impaired absorption of other minerals. In rare cases, extremely high calcium intake can lead to kidney failure and cardiovascular issues. Ideally, you should get your dietary calcium mainly through plants to avoid the adverse health consequences associated with dairy consumption
[1] https://www.hsph.harvard.edu/nutritionsource/calcium/[2] https://www.ncbi.nlm.nih.gov/books/NBK56056/[3] https://www.dietaryguidelines.gov/food-sources-calcium[4]Ann Nutr Metab. 2018;73 Suppl 4:30-37. [5] Clin Pediatr (Phila). 2016 Oct;55(11):1054-63.[6] Foods. 2018 Mar 1;7(3):29[7] Iran J Public Health. 2015 Jun;44(6):742-58.[8] Nutrients. 2018 Aug 9;10(8):1049[9] International Journal of Disease Reversal and Prevention,2023 Vol 5(1), 14[10] Crit Rev Food Sci Nutr. 2020;60(10):1722-1737.[11] Clin Interv Aging. 2018 Nov 28;13:2443-2452
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