Osteoporosis

Osteoporosis is one of the most common disorders in Germany in which nutrition plays a contributory role. Its pathogenesis often spans decades. Under certain conditions athletes are also at risk. Regular monitoring of the dietary intake and the state of nutritional health help reveal possible deficits and imbalances, and contribute toward the prevention of osteoporosis by the application of suitable nutritional measures [1, 2].

Osteoporosis is a systemic disease of the skeleton. The low bone mass and the microarchitectural deterioration of the bone tissue lead to increased bone fragility and susceptibility to fractures. The peak age in men and women is over 70, which is explained by multifactorial influences and the insidious pathogenesis. A basic distinction is drawn between primary and secondary osteoporosis. Primary osteoporosis does not develop on the basis of an underlying disease [2].

Risks of osteoporosis in sports

All physical activities and sports contribute towards the prevention of osteo­porosis. Athletes are at a higher risk of osteoporosis if they are subject to long-term malnutrition and dietary deficiency. This primarily affects athletes with a BMI < 20, and/or those whose restrictive nutritional intake supplies insufficient nutrients [1, 3]. One-sided nutrition or an overlooked increased requirement can favour a deficiency of certain nutrients in the long term and promote the onset of osteoporosis [4]. From the aetiological viewpoint, the consequences of malnutrition and deficiencies of certain nutrients (e.g. calcium, vitamin D) during adolescence and young adulthood often only become apparent decades later. This is compounded by the fact that some athletes have increased requirements of certain nutrients, e.g. protein, iron, depending on the type of sport and the degree of exertion [3].

A nutritional expert can calculate the early indications of athletes’ nutrient intake and the status of nutritional supply by conducting a nutrient analysis. Possible deficits can be remedied successively by initiating individual interventions. Among others, these involve changing the choice of foodstuffs and, if necessary, taking supplements for deficient nutrients (after consulting a doctor). Medical examinations, e.g. of the blood during osteoporosis screening, give sound information about the supply of nutrients. If a long-term inadequate calcium supply is suspected the examination can be augmented by osteodensitometry. In case of inadequate supply, or with early or existing osteoporosis, medical interventions are initiated and supplemented by individual nutritional measures if necessary [5].

Key nutrients and stimulants

An adequate supply of calcium and vitamin D are important elements in the prevention of osteoporosis [1, 6]. Vitamin K2 also plays an important role in preventing osteoporosis. However, recommendations for supply and supplementation are not yet anchored in the German Association of the Scientific Medical Societies (AWMF) guideline „Prophylaxis, diagnosis and treatment of osteoporosis“. There is strong evidence that permanent calcium and vitamin D deficiencies influence the onset of osteoporosis [1]. While calcium is one of the components of bone, vitamin D promotes the absorption of calcium from the gastrointestinal tract and helps harden the bone. Vitamin D also regulates calcium and phosphate metabolism [7]. However, 74 % of female adolescents aged between 14 and 18 fall short of the recommended calcium intake. In elderly men and women aged 65 – 80 these figures are 61 % and 65 % respectively [8]. With regard to the supply of vitamin D, the recommended intake is below the reference level in 91 % of women, and in men this figure is 82 % [8]. Since the substance is synthesised in the skin exposed to UVB radiation, humans do not depend solely on the supply of dietary vitamin D. Theoretically, UVB radiation is sufficient to ensure an adequate supply between April and October in Germany. Nevertheless, approx. 60 % of the German population is considered to have an inadequate intake [5]. Consequently, athletes can also be affected. 

An excessive supply of certain nutrients in sports can also favour the onset of osteoporosis. For instance, excessive protein intake also boosts the excretion of calcium in the urine. The same applies to the excessive consumption of coffee containing caffeine, although 3 – 4 cups a day are still considered safe. Immo­derate alcohol consumption (men > 20 g/ day, women >10 g/ day) has negative effects on osteoblast function and, as a result, increases the risk of osteoporosis [9 – 11]. While an excessive intake of protein promotes the excretion of calcium, a deficit should also be avoided: too little protein in the long term inhibits the collagen structure of the bones and, due to loss of muscle mass, increases the risk of falling [12]. More recent findings show that a protein intake of 1.2 – 2.0 g per kg bodyweight for athletes who do more than five hours of endurance sports per week provides a useful contribution to protein biosynthesis [13]. The study situation for other micronutrients is less well researched: folate, vitamin B6, vitamin B12, vitamin K, potassium, fluoride and silicon are examples of micronutrients that contribute towards the normal function of bone metabolism. Glucosamine and chondroitin sulphate are endogenous substances. They are components of the connective and cartilaginous tissues. The substances can be used at a sufficiently high dosage to treat existing osteoarthritis. The same applies to the omega-3 fatty acid eicosapentaenoic acid (EPA). The outcome of a cross-sectional study shows that the adequate intake of potassium and magnesium correlates positively. The following applies to athletes and everybody else: a high intake of fruit and vegetables in childhood contributes towards higher bone density of the femoral neck [14].

Vegetarian and vegan nutrition

Although vegetarians and vegans are often claimed to have an inadequate calcium intake, vegetarians are more rarely affected by increased loss of bone mass than omnivores. It is thought that a vegetarian diet, in part high in calcium and, at the same time, low in dietary phosphate, exerts beneficial properties in retaining bone mass. At the same time, the reduction in animal protein can exert a calcium-sparing effect. According to current understanding vegans too, who eat more than 525 mg calcium daily, are not at higher risk of osteo­porosis [5]. 

Case study 

Lisa A.: triathlete, 32-years-old, BMI 19.1, 12 hours of endurance sports per week, vegan lifestyle. Lisa A. refuses vegetarian foodstuffs that have been enriched with calcium, Vitamin B12 and other micronutrients. A BMI of < 20 is principally a risk factor for the danger of osteoporosis. From a BMI of 18.4 adult women are classified as underweight. A nutritional behaviour of avoiding enriched milk substitutes can be a problem. It can lead to deficits of calcium and Vitamin B12 among others. Saltwater fish is the best dietary source for supplying vitamin D. This nutritional source is not available on a vegan diet. Possible nutritional measures: if the review of the supply of nutrients as part of a nutritional analysis shows that there are deficits, the following recommendations are conceivable: 

• Bodyweight: increase daily energy supply by about 300 kcal, e.g. 1 – 2 slices of wholemeal bread with humus and one portion of vegetables.
• Calcium supply: eat calcium-rich vegetables and pulses daily, e.g. broccoli, kale, tofu and mung beans, and drink calcium-rich mineral water (>150 mg/ calcium per litre).
• Vitamin B12 supply: ensure a supply of Vitamin B12 with alcohol-free wheat beers, bread drink, enriched toothpaste, and possibly with supplements.
• Vitamin D supply: regular medical tests of the supply of vitamin D in the blood, if necessary take supplements, above all in winter.
• Vitamin K2 supply: ensure the supply with fermented foodstuffs such as sauerkraut and with supplements if necessary, perhaps in combination with vitamin D3. Regular medical checks on the supply are recommended.
• Recommended intake of relevant nutrients (excerpts)

Calcium [15]

Age	mg / day
7 to under 10 years	900
10 to under 13 years	1100
13 to under19 years	1200
19 years and older	1000
Nursing and pregnant women	1000

Vitamin D (if there is no endogenous synthesis) [16] 

Age	µg*/ day
0 to under 12 months	10
From the first year of life	20
Nursing and pregnant women	20

*1µg is equivalent to 40 IU (International Units)

Summary

Osteoporosis is a disease in which nutrition plays a contributory role. It can often be prevented by an adequate supply of nutrients in combination with sport. Nevertheless, athletes are also exposed to an increased risk of the disease, not only due to their low bodyweight, but also to inadequate/erroneous eating habits. An adequate supply of calcium and vitamin D is vital for preventing osteoporosis. Furthermore, other macro- and micronutrients influence bone metabolism. Athletes should always have their supply of nutrients checked by nutritional experts using nutrient analysis and by doctors testing laboratory parameters. In this manner possible deficits or imbalances can be revealed early and remedied with suitable interventions.

Reference

[1] AWMF (2019). Langfassung der Leitlinie „Prophylaxe, Diagnostik und Therapie der Osteoporose. https://www.awmf.org/uploads/tx_szleitlinien/183-001l_S3_Osteoporose-Prophylaxe-Diagnostik-Therapie_2019-02.pdf (07.07.2021).

[2] Barth, S. (2009). Ernährungsmedizin. München: Urban & Fischer.

[3] Carlsohn, A., Braun, H., Großhauser, M. et al. (2019). Mineralstoffe und Vitamine im Sport. Ernährungs Umschau 66(12):250 – 257.

[4] Vohland, V., Heil,. E. (2020). Ernährungsökologische Betrachtung von veganer Ernährung. Ernährungs Umschau – Sonderheft 5.

[5] Stange, R., Leitzmann, C. (2018). Ernährung und Fasten als Therapie. 2. Aufl. Berlin: Springer.

[6] Scheck, A. (2017). Ernährungslehre kompakt. 6. Aufl. Wiesbaden: Umschau Zeitschriftenverlag.

[7] Gröber, U. (2011). Mikronährstoffe. 3. Aufl., Stuttgart: Wissenschaftliche Verlagsgesellschaft.

[8] MRI – Max Rubner-Institut, Bundesforschungsinstitut für Ernährung und Lebensmittel (2008). Nationale Verzehrsstudie II – Ergebnisbericht Teil 2 – Die bundesweite Befragung zur Ernährung von Jugendlichen und Erwachsenen. https://www.mri.bund.de/fileadmin/MRI/Institute/EV/NVSII_Abschlussbericht_Teil_2.pdf (02.07.2021).

[9] Malik, P. (2008). Alkoholinduzierte Reduktion der Knochenmineraldichte: eine Übersicht. J Miner Stoffwechs 15(3):123-128.

[10] Bartl, R., Bartl, Ch. (2011). Osteoporose. Prävention, Diagnostik, Therapie. 4. Aufl. Stuttgart/ New York: Thieme.

[11] Zittermann, A. (2007). Osteoporose. Ernährungs Umschau 11:B33-B36.

[12] Rapur, P.B., Gallagher, J.C., Haynatzka, V. (2003). Protein intake: effects on bone mineral density and the rate of bone loss in elderly woman. Am J Clin Nutr 77(6):1517-1525.

[13] König, D., Carlsoh, A., Braun, H. et al. (2020). Proteinzufuhr im Sport. Ernährungs Umschau 67(7):132-139.

[14] New, S.A., Robins, S.P., Campbell, M.K. et al. (2000). Dietary influences on bone mass and bone metabolism: further evidence of a positiv link between fruit an vegetable consumption and bone health? Am J Clin Nutr 71(1):142-151.

[15] Deutsche Gesellschaft für Ernährung (DGE) (2013). Referenzwerte – Calcium. https://www.dge.de/wissenschaft/referenzwerte/calcium/?L=0 (07.07.2021).

[16] Deutsche Gesellschaft für Ernährung (DGE) (2012). Referenzwerte- Vitamin D (Calciferole). https://www.dge.de/wissenschaft/referenzwerte/vitamin-d/?L=0 (07.07.2021).

 

Buchtipp der Redaktion

Power für die Knochen

Osteoporose vorbeugen, diagnostizieren, behandeln

Schätzungen zufolge erleidet jede zweite Frau und jeder fünfte Mann im Laufe seines Lebens
einen Knochenbruch durch Osteoporose. Dabei betrifft diese Krankheit keineswegs nur Ältere.
Schon in jungen Jahren kann durch Übergewicht, falsche Ernährung oder Bewegungsmangel der
Grundstein für spätere Beschwerden gelegt werden.

Dr. Bartl zeigt in „Power für die Knochen“, dass Osteoporose keineswegs eine schicksalhafte
Begleiterscheinung des Alterungsprozesses ist, die man hinnehmen muss. Dank Fortschritten in
der operativen Frühversorgung sowie dem Einsatz der neuesten Medikamente ist sie heute eine gut
behandelbare und im Frühstadium sogar heilbare Erkrankung. So kann der Knochen wieder stabilisiert werden und vor allem Folgefrakturen vermieden werden. Es ist nie zu spät, den Kampf gegen die Osteoporose aufzunehmen und für mehr Mobilität und ein starkes, lebendiges Skelett zu sorgen.

Das Buch enthält Übungen, Fragebögen, Vorsorgetipps und Ernährungsratschläge, beispielsweise
die 10 Gebote der Rückenschule, den Osteoporose-Risikotest oder die Checkliste für Patienten.

Reiner Bartl
Power für die Knochen
Osteoporose vorbeugen, diagnostizieren, behandeln
Mit Vorwort von Marianne Koch
In Zusammenarbeit mit Johanna Fellner
Paperback , Klappenbroschur, 192 Seiten, 17,0 x 24,0 cm
ca. 70 farbige Abbildungen
ISBN: 978-3-517-10074-6
€ 20,00 [D] / € 20,60 [A] / CHF 28,90
Südwest Verlag

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