Monday, October 13, 2008
Eating for bone strength

World Osteoporosis Day occurs on Monday October 20th and the National Osteoporosis Society (NOS) is running a UK-wide campaign ‘Love Your Bones’ which is intended to raise awareness about the importance of healthy bones.  The goal of the National Osteoporosis Society is to improve understanding of osteoporosis, what causes it and to promote the steps people can take to keep their bones healthy and reduce their risk.


“Osteoporosis literally means ‘porous bones’. Our bones are made up of a thick outer shell and a strong inner mesh which looks like a honeycomb made up of tiny struts of bone. Osteoporosis means some of these struts become thin or break, making bones more fragile and prone to fracture. It often remains undetected until a bone is first broken, which commonly occurs in the wrists, hips and spinal bones. It is these broken bones or fractures which can lead to the pain associated with osteoporosis. Spinal fractures can also cause loss of height and curvature of the spine.”(1)


Please visit the NOS for loads more information on bone health.  They have many online and downloadable resources, including a booklet ‘Healthy Eating For Strong Bones’ and a page dedicated to the ‘Sunlight Campaign’ which highlights the fact that sunlight is one of the very best natural sources of vitamin D, a vitamin that is essential for the building of healthy bones and the prevention of osteoporosis.  The NOS point out that up to 15 % of people in the UK are estimated to have low levels of vitamin D, while 80% have levels which are considered unhealthy.  There have now been many calls for a revised vitamin D intake recommendation in the UK(2) due to extensive evidence of low levels. The NOS website provides simple tips for boosting your vitamin D levels.


Calcium and Vitamin D
A recent review paper(2) looked at the evidence surrounding the importance of calcium and vitamin D for bone health and the prevention and treatment of osteoporosis.  The paper points out that an estimated one in three women and one in twelve men aged over 55 years will suffer from osteoporosis in their lifetime.  This represents a huge cost in the UK (many millions of pounds per year).  Calcium supplements appear to be effective in reducing bone loss in women in late post menopause (after five years), particularly in those with a low daily calcium intake (less than 400 mg/d).  Supplementation with vitamin D and calcium has also been shown to reduce fracture rates in some elderly populations. Low vitamin D status is associated with an increased risk of falling and a variety of other health outcomes and is an area that requires urgent attention.


It is very important to consider bone health at an early age, this is because peak bone mass (peak bone strength) is reached before the age of 30, after this age bone gradually grows weaker.  Building up great bone strength early on in life will help reduce the risk of osteoporosis later in life.  Most studies show that calcium, supplemental or high dietary intake, is important in at a young age in order to reach a good peak bone mass (3), 600mg-1,000mg calcium daily before the age of 25 may be beneficial to reaching a good bone mass.  As mentioned above evidence regarding supplementation later in life is mixed.  However, a supplement containing vitamin D and calcium could be useful in maintaining bone mass (providing around 800mg calcium daily and 20mcg/800IU vitamin D).


Other nutrients
The role of other nutrients on bone remains to be fully defined(2), although there are promising data in the literature for links between various nutrients including: magnesium, zinc, copper, potassium, silicon, manganese, vitamin K, vitamin C, vitamin B and phytonutrients (biochemical plant compounds).  A varied, healthy diet, especially on rich in fruits and vegetables, will provide a huge array of nutrients that may positively impact bone health.  If you feel your diet is lacking you may wish to consider a high quality food-state multi-vitamin and mineral supplement.  This is NOT a substitute for good dietary habits!! 


Omega 3 fatty acids
Yes, it is the fish oils making an appearance again!  Eating a diet rich in the omega 3 fatty acids EPA and DHA, found in oily fish such as mackerel, salmon and sardines, may contribute to a reduced risk of osteoporosis by inhibiting the production of pro-inflammatory chemicals (eicosanoids) that are known to be involved in the process of bone loss.  This is a relatively new field of interest in osteoporosis.  Two recent reviews (4,5) looked at the evidence so far which does indicate a benefit, though the authors point out that further evidence is needed before firm conclusions can be drawn.  However, due to the numerous health benefits of omega 3 fatty acids (see previous blog posts) I would suggest the regular inclusion of oily fish in the diet (at least twice weekly), or taking a supplement providing around 250mg EPA and 250mg DHA a day.  For vegetarians I would suggest a daily flaxseed oil supplement to provide around 500mg alpha-linolenic acid (a shorter chain omega 3 fatty acid).

 

Fruits and Vegetables
A number of studies over the last decade have suggested a clear, positive link between fruit and vegetable consumption and bone health(6).  These foods provide a huge range of nutrients that are important for bone health.  In addition to the nutrients fruit and vegetables positively affect the pH balance (a measure of acid-alkali balance) in the body, by increasing the alkalinity in the body (making the body less acidic), which plays a major role in the prevention of calcium loss from bones.  Foods which are acid forming in the body include foods such as most meat and animal protein, cheddar cheese and many grain products e.g. white bread, pasta, cornflakes.  If the body is too acidic, not in pH balance, then bones can release their calcium (which increases alkalinity) into the blood to try and maintain the balance.  Obviously calcium loss is not what we want!!  Providing the body with abundant supplies of vegetables and fruits may well help to keep our bones strong as well as protecting us from many other diseases.


If you drink a lot of caffeinated tea, coffee or regularly consume fizzy drinks you may wish to reduce the amount you consume in order to protect your bones.  High intakes of these drinks can have a negative effect on bones.  The phosphoric acid they contain may cause calcium loss from bones.


Visit the National Osteoporosis Society website for more information


(1)The National Osteoporosis Society
(2) New-Lanham SA.  2008.  Importance of calcium, vitamin D and vitamin K for osteoporosis prevention and treatment.  Proc Nutr Soc.  67(2):163-76.
(3) Eastell R & Lambert H.  2002.  Strategies for skeletal health in the elderly.  Proc Nutr Soc.  61:173-180
(4)Salari P et al.  2008.  A systematic review of the impact of the impact of n-3 fatty acids in bone health and osteoporosis.  Med Sci Monit.  14:RA37-44
(5)Fernandes G et al.  2008.  Effects of n-3 fatty acids on autoimmunity and osteoporosis.  Front Biosci.  13:4015-4020
(6) New SA.  2003.  Intake of fruit and vegetables:implications for bone health.  Proc Nutr Soc.  62:889-899

Written by Ani Kowal

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