Episode 63 – Bone Health & Nutrition

Key Topics Covered

Bone health is clearly important for several reasons. It supports:

Longevity (maintain independence for longer, stay active for longer + the carry-over reason of staying active)
We’ve also done research in this area, so we find it super interesting

Calcium

Recommended daily intake is:
- 1000mg/day for adults
- 1300mg for post-menopausal people and men over 70
Average calcium intake in Australia
- 850mg – This means that the people below this average are also quite some way below the RDI.
A longitudinal study on dietary calcium intake and hip fracture risk found that increasing calcium intake from lower levels up to around 750mg reduced the risk of hip fractures, but going higher did not seem to provide further benefits.
- Any study measuring the dietary intake of a single nutrient will have a lot of confounding variables though. For example – increasing dietary calcium likely increases protein, potassium, magnesium, zinc, phosphorus, and calorie intake amongst other things. These all play a role in bone health.
Supplementing dosages such as 1200mg of calcium per day has been shown to be effective for improving bone mineral density and reducing fractures risk,
- This was in research where baseline dietary calcium intake was not factored in. But this dosage of supplementation also appears more effective than lower dosages as well.

Dairy + Calcium Combination Thoughts/Controversy

There is a Harvard study that was done on milk in 1997 that showed no link between higher milk consumption or other food sources of calcium and a reduction in hip or forearm fractures.
This study is often pointed to by people who are trying to make a case against dairy.
But this study really is an outlier. The vast majority of the rest of the research on both calcium and dairy show that it increases bone mineral density.

Vitamin D

A meta-analysis found that supplementing 700-800IU of vitamin D per day improved bone mineral and density reduced the risk of fractures in those over the age of 60 years old, while 400IU was insufficient.
That was just an across the board protocol though. Further individualisation would like further improve results. Measuring blood levels of vitamin D at the baseline and then rectifying them to the point that they were at the optimal range would like improve results further. For some people this will take significantly higher dosages.
Vitamin D has the additional benefit of improving balance too which could reduce falls risk a little bit as well.
An alternative could just be to get more sun too – while obviously balancing this with skin cancer risk.

Vitamin K

Low vitamin K intake has been linked with reduced bone mineral density and increased fractures risk.
The optimal vitamin K intake has been proposed to be 90 micrograms per day,
- whereas it is estimated that less than half the population reaches this amount, and ¼ is at <60 micrograms.
Vitamin K supplementation protocols using >100 micrograms per day have been shown to reduce fractures risk.
The research on supplementation did not also find an improvement in bone mineral density – the authors proposed that bone strength was improved without increasing the mineral content. This is obviously complicated because as mentioned previously low vitamin K intake has been linked with low bone mineral density.

Magnesium

A 2-year study in women with osteoporosis found that supplementing 250mg of magnesium per day significantly improved bone mineral density.
If not mentioned already, now is probably a good time to mention that it is clear that we can still increase/re-increase bone mineral density late in life under the right circumstances. It is not like it is a finite resource that we are just trying to preserve.
The RDI for magnesium in Australia is 310mg-420mg depending on age/gender. I don’t have specific numbers, but most people likely fall short of this target.

Zinc

This is less strongly linked than the stuff mentioned previously, but low zinc intake is associated with lower bone mineral density.
Obviously just assessing dietary intake has the flaw of all the other variables.
To build a stronger case though – a study on zinc supplementation in a group of people with osteoporosis AND a zinc deficiency found that following supplementation, bone mineral density increased.
This information likely is not useful for the majority of people – but if you have a low zinc intake (maybe more relevant for people who are plant based) or are at risk of a deficiency, then it would be worth being aware of.

Protein

Bone is made up of ~90% collagen, which is a protein source. So obviously protein intake plays a role.
Clearly excessively low protein intake would have to be detrimental for bone mineral density. But a lot of people claim high protein intake is bad for bone mineral density.
The main claim regarding this is called the acid-ash hypothesis, which stems from the alkaline diet.
This hypothesis claims that consuming acid producing foods such as excessive amounts of protein would cause the body to try to counteract the additional acidic load by breaking down bone to balance things out, which would lead to weaker bones and osteoporosis.
This is an easy claim to debunk though – if this hypothesis is true, then on average we should see that higher protein intakes lead to reduced bone mineral density.
When looking at the research on protein intake and bone mineral density though, that isn’t the case. On average bone mineral density is higher in those with higher protein intake.
The current consensus is to not go out of your way to go beyond >2g/kg per day without reason. But there is no need to actively reduce it.
From another perspective, falls risk is a major factor here too. Higher protein intake typically reduces the risk of falls too.

Other stuff

Collagen supplementation has a bit of evidence that it can help – but it is still early and there is not much research to make strong claims about
Boron: A systematic review showed that supplementing with 3mg of boron per day increases bone mineral density. The mechanism is due to the role it plays in calcium and vitamin D metabolism. The upper limit is 10mg per day, so the authors proposed that there was minimal downside to this approach. This is such a niche area that there isn’t even an RDI for boron yet, although it is estimated that the average intake through food is around 1.2mg per day.
Increased potassium intake is linked with increased bone mineral density. But it is hard to tell if the benefit is actually due to potassium, or because potassium rich foods are high in other nutrients like magnesium which are associated with bone health.

Summary

Other thoughts on what things we should supplement with?
- Calcium – if someone has low calcium intake
- Vitamin D – if they have low vitamin D levels on their blood test
- The other nutrients we’d probably look at getting it through food

Relevant Links/ Resources

Studies Mentioned