Nutrition Library

Calcium

General Information
  • Calcium is the “bone mineral.” It is the most abundant mineral in the body (approx. 1 kg), approx. 99% of which is bound in the skeletal system.
  • The German population is, in general, adequately supplied with calcium.
  • Calcium intake is also generally sufficient in the USA. Groups with insufficient intake include children and teens (both girls and boys).
  • Several studies from Great Britain found that calcium can be a critical nutrient in the vegan diet. Vegans often do not consume the recommended amount.
  • Excessive calcium intake is frequently found among older women in Europe and the United States; this is due to their consumption of dietary supplements with a high calcium content.
Why Do We Need Calcium?
  • For mineralization and strength of the bone tissue and teeth
  • Important for transmission of stimuli in nerve and muscle cells (e.g., electromechanical coupling, influencing membrane potential and permeability)
  • Activation of the blood coagulation system
    • Cofactor of many enzyme functions (e.g. alkaline phosphatase, glycolysis, gluconeogenesis)
    • One factor in hormone balance, e.g., influences insulin release from beta cells in the pancreas
    • Important in maintaining cell function (stabilization of cell membranes, cell differentiation)
    Possible Reasons for Calcium Deficiency

    Low intake:

    • Diet contains few calcium-rich foods (see below)

    Increased intake requirements:

    • Childhood, pregnancy, breastfeeding, growth periods
    • Age-related malabsorption

    Reduced absorption:

    • Vitamin D deficiency, magnesium deficiency
    • Intake of phosphates (e.g., in soft drinks)
    • Intake of oxalates (in rhubarb, spinach, beetroot, beans, cocoa powder)
    • Alcohol intake
    • Excessive salt, sugar, protein, or fat intake
    • Bowel diseases such as chronic inflammatory diseases, celiac disease, short bowel syndrome, etc.

    Increased excretion:

    • High coffee consumption (> 4 cups / day)
    • Caused by medication such as ASA, furosemide, glucocorticoids

    Interaction with medication:

    • For example, antacids, antiepileptics, PPI, glucocorticoids, L-thyroxine, laxatives, etc.

     

    → in general, optimal calcium utilization in the body depends on an adequate vitamin D level!

    Symptoms of Deficiency
    • General: muscle cramps, weakness
    • Eyes: increased risk of cataract formation
    • Blood: impaired blood clotting
    • Bone metabolism: decrease in bone density in the hip and spine, demineralization of the skeleton, tendency to bone fractures, osteoporosis
    • Muscles/nerves: cardiac arrhythmia, excessive neuromuscular excitability, paresthesia, especially in fingertips and toes
    Recommended Intakes

    Recommended intake for adults:

    • German/Austrian/Swiss recommendation (D-A-CH): 1000 mg / day
    • USA Food and Nutrition Board (FNB): 1000 mg/day, women age 51+ 1200 mg/day, men 70+ 1200 mg/day

    Pregnant women (> 19 years):

    • according to D-A-CH: 1000 mg/day
    • USA Food and Nutrition Board (FNB): 1000 mg/day

    Breastfeeding women:

    • according to D-A-CH: 1000 mg/day
    • USA Food and Nutrition Board (FNB): 1000 mg/day

    Children, depending on age:

    Excessive calcium intake (> 2,500 mg/day, according to the European Food Safety Authority and in the USA) should be avoided. This level is usually only achieved with supplements in addition to a calcium-rich diet. Supplementation is increasingly common and is intended to prevent osteoporosis. In addition to gastrointestinal complaints, such as constipation, side effects include significantly increased risk of arteriosclerosis, high blood pressure, and cardiovascular diseases; this has been demonstrated by an increasing number of studies where supplemental calcium intake (not natural calcium in the diet!) exceeded the above-mentioned limit.

      The Best Plant Sources (per 100 g)

      Good plant sources of calcium sources include seeds, nuts, soy, and green vegetables:

      • Sesame – 783 mg
      • Nettle – 713 mg
      • Almonds – 252 mg
      • Hazelnuts – 225 mg
      • Kale – 212 mg
      • Flax seeds – 198 mg
      • Tofu (made with calcium sulfate) – 185 mg
      • Arugula – 160 mg
      • Pistachio nuts – 136 mg
      • Brazil nuts – 132 mg
      • Plant milks with added calcium – 120 mg
      • Soybeans, cooked – 89 mg
      • Walnuts – 87 mg
      • Kohlrabi – 59 mg
      • Broccoli – 58 mg
      Sources
      • https://www.mri.bund.de/de/institute/ernaehrungsverhalten/forschungsprojekte/nvsii/
      • Davey G, Spencer E, Appleby P, Allen N, Knox K, Key T. EPIC–Oxford:lifestyle characteristics and nutrient intakes in a cohort of 33 883 meat-eaters and 31 546 non meat-eaters in the UK. Public Health Nutrition 2003; 6(3), 259-268.
      • Clarys P, Deliens T, Huybrechts I, Deriemaeker P, Van Aelst B, De Keyzer W et.al. Comparison of Nutritional Quality of the Vegan, Vegetarian, Semi-Vegetarian, Pesco-Vegetarian and Omnivorous Diet. Nutrients 2014; 6(3), 1318-1332.
      • Gröber, U. (2011): Mikronährstoffe. Metabolic Tuning – Prävention – Therapie. 3. Aufl. Wissenschaftliche Verlagsgesellschaft mbH Stuttgart
      • https://www.dge.de/wissenschaft/referenzwerte/calcium/
      • Tankeu, AT, Ndip Agbor, V, Noubiap, JJ. Calcium supplementation and cardiovascular risk: A rising concern. J Clin Hypertens. 2017; 19, 640646
      • Xiaoyan Wu MD , Tianshu Han MD , Jian Gao MD , Yunlong Zhang MD , Shengnan Zhao MD , Rongbo Sun MD , Changhao Sun MD , Yucun Niu MD. Association of Serum Calcium and Insulin Resistance With Hypertension Risk: A Prospective Population‐Based Study. Journal of the American Heart Association 2019; 8(1)
      • Bolland MJ, Avenell A, Baron JA, Grey A, MacLenan GS, Gamble GD, Reid IR. Effect of calcium supplements on risk of myocardialinfarction and cardiovascular events: meta-analysis. BMJ 2010; 341:c3691