How can diet affect our bone health?

Our bones are of course essential for making up the framework of our body, but they are also important for storing calcium. This store is what maintains the levels of calcium in our blood via a very tightly regulated system, which is essential for things like muscle contraction and normal blood clotting. This means calcium (and Vitamin D) are key when it comes to supporting bone and joint health. Calcium and vitamin D go hand in hand as vitamin D aids the absorption of calcium.

RECOMMENEDED INTAKES

  • Calcium recommendation for adults = 700 mg/day
  • Vitamin D recommendation for adults = 10 mcg (micrograms)/day

In the UK, milk and milk products, such as cheese and yoghurts, account for almost half of all calcium intake in adults. But, with more and more people transitioning to a vegan diet or reducing their consumption of animal products, it is important to focus on including vegan sources of calcium in your diet. Luckily, a lot of plant-based foods are high in calcium, such as tofu, soya beans, tahini, nuts and anything made with fortified flour including cereals and bread.

What could 700 mg of calcium per day look like?

  • Breakfast: fortified wholegrain cereal/muesli containing dried fruit with milk/fortified non-dairy milk
  • Lunch: chickpea curry with chapati (fortified flour) and yoghurt/fortified non-dairy yoghurt
  • Dinner: Tofu stir fry with lots of leafy green vegetables such as broccoli, kale, bok choy etc. topped with chopped nuts

Vitamin D is much harder to get from our diet, although it is found in eggs, oily fish and fortified spreads and breakfast cereals. From April to September most people can make enough Vitamin D from sunlight, but since we’re all spending a lot more time inside anyway, you should cover your bases with a supplement. The NHS recommends everyone over the age of 5 to take a daily supplement of 10 micrograms of vitamin D a day.

WHAT ABOUT VITAMIN K?

Vitamin K is also vital for bone health as it produces an amino acid called Gla, which essentially acts like glue to help keep calcium in the bone. Food sources of Vitamin K include green leafy vegetables, meat and dairy products and Japanese natto (fermented soybeans).

A study by Cheung et al. looking into postmenopausal women found that supplementing with high doses of vitamin K (5 mg/day) over 4 years reduced the incidence of fractures. However, lots more research is needed in this area to determine the benefits of vitamin K on bone health.

WHAT IS PEAK BONE MASS?

Bone is a living tissue that is constantly removed and replaced by new bone. Peak bone mass is the greatest amount of bone an individual can attain, and a high peak bone density reduces your risk for osteoporosis later in life. Peak bone mass is around 80% determined by your genetics and the other 20% is down to environmental factors, such as nutrition and physical activity. The majority of peak bone mass is laid down during puberty, so this is an important stage to focus on adequate calcium intake. However, in recent years, data from the NDNS has shown that calcium intakes are actually lowest in 19–24-year-olds, and the average intake for girls is much lower than boys. It’s also important to note that 1-2% of bone is lost during menopause over a 5–10-year time span, so it is especially vital that girls reach peak bone mass to reduce their risk of osteoporosis. 

JOINT HEALTH

Our joints are what allow us to bend our knees to do squats, hula-hoop with our hips and move your thumbs to scroll through Instagram – important stuff! However, arthritis is a common condition causing inflammation in the joints, affecting more than 10 million people in the UK.

One Swedish study in 2013 found that eating long chain n-3 polyunsaturated fatty acids (n-3 PUFAs) aka omega-3 fatty acids could halve the risk of arthritis. They assessed women over a decade and found that those with intakes of more than 0.21 g per day were associated with a 35% reduced risk of arthritis. Even more interestingly, they found that more than a quarter of rheumatoid arthritis cases could be avoided if everyone had an intake of more than 0.21 g a day.

What does 0.21g/day of n-3 PUFAs look like?

  • Less than ¼ of a tin of mackerel  
  • About ¼ of a salmon fillet
  • 2 eggs
  • 2 tbsp of olive oil
  • 1 tsp of flax seeds

We can’t say that n-3 PUFA’s are directly responsible for this result, as other factors are likely to be at play, such as those with high intakes may have had a healthier diet overall or other healthy lifestyle behaviours. However, it is generally recommended that we eat 2 portions of fish a week, one of which should be oily (e.g. mackerel, salmon, sardines, trout etc.)

REFERENCES

https://adc.bmj.com/content/90/4/373

https://www.bones.nih.gov/health-info/bone/osteoporosis/bone-mass

https://www.nhs.uk/live-well/healthy-body/food-for-strong-bones

https://pubmed.ncbi.nlm.nih.gov/21839190

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2566998

https://ard.bmj.com/content/73/11/1949

Contribution from Sophie Gastman ANutr 

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