Recently I attended a seminar which concentrated on bone health in women going through the menopause.  The decrease in blood serum oestrogen after menopause is associated with bone loss and subsequent brittle bones and osteoporosis.

A study(1) was briefly mentioned at the seminar which seemed to suggest that onion consumption was linked to bone health in peri- and post-menopausal women.  I was intrigued!  The study found that individuals who consumed onions once a day or more had an overall bone density that was significantly greater than individuals who consumed onions once per month or less.  This association was apparent even after the authors took various other factors (that can affect bone health) into account such as age, body mass index (BMI), daily calcium intake, serum vitamin D, serum parathyroid hormone, oestrogen use, smoking status, and exercise status.  This suggests that onion consumption may be an independent factor in bone health. The study also found that older women who consume onions most frequently may decrease their risk of hip fracture by more than 20% versus those who never consume onions.

Why would onions be having this kind of effect? A possible explanation could be that onions contain a flavonoid (bioactive plant compound) called quercetin which has antioxidant and anti-inflammatory actions in the body and has been linked with protecting against heart disease, cancer and asthma.  Quercetin is also found in apples and grapes.  Two laboratory studies (2,3) last year found that quercetin could increase new bone formation.

Quercetin is also classes as a phytoestrogen.  Phytoestrogens are natural plant-derived compounds that bind to oestrogen receptors and have oestrogen-like activity in the body.  Recently phytoestrogens have attracted much attention among public and medical communities because of their potential beneficial role in prevention and treatment of cardiovascular diseases, osteoporosis, diabetes and obesity, menopausal symptoms, renal diseases and various cancers.

Our bone cells (osteoblasts) have two oestrogen receptors on their surface and certain phytoestrogens, including quercetin, can interact with these oestrogen receptors in bone.  It is possible that quercetin binds to the bone oestrogen receptors and stimulates and increases bone formation and bone mineralisation.  Further studies are needed to investigate these ideas. The authors of one of the studies say (3)“If quercetin, this common constituent in fruits and vegetables, can be shown to increase bone forming activities in bone cells and improve healing in bone defects, it may be the long-sought-after safe and ideal agent for stimulation of bone formation and bone defect repair”

Onions are one of my favourite vegetables and easy to integrate into meals and salads.  Apples and grapes are also easily incorporated into the daily diet.  Last year I wrote about the importance of fruit and vegetables for bone health.  A number of studies over the last decade have suggested a clear, positive link between fruit and vegetable consumption and bone health.  These foods provide a huge range of nutrients that are important for bone health.  In addition to the nutrients, fruit and vegetables positively effect 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, and 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, especially those high in quercetin, may help to keep our bones strong as well as protecting us from many other diseases.  Quercetin supplements are also readily available to buy, usually as an antioxidant boost for the body and for allergy prevention and treatment, although their impact on bone health have not yet been tested. 

Please also read my other various posts on osteoporosis for more information on how to keep bones healthy

(1) Matheson EM et al.  2009.  The association between onion consumption and bone density in perimenopausal and postmenopausal non-Hispanic white women 50 years and older. Menopause.  16(4):756-9.
(2) Wong RW & Rabie AB.  2008.  Effect of quercetin on bone formation. J Orthop Res.26(8):1061-6.
(3)Wong RW &  Rabie AB.  2008.  Effect of quercetin on preosteoblasts and bone defects. Open Orthop J. 10;2:27-32.

Written by Ani Kowal

In October of last year I wrote about eating for bone health and mentioned the clear and positive associations between fruit and vegetable consumption and strong bones (1).  The post concentrated mainly on the way these foods act to effect the pH balance within the body.  Fruits and vegetables contain a huge array of vitamins, minerals and phytonutrients/flavonoids (chemically active plant compounds) that may also act to strengthen bone.

Last month a paper was published in the American Journal of Clinical Nutrition (2) which points toward the bone protective effects of carotenoids.  Previous evidence suggests that carotenoids may be acting to prevent bone loss and also to stimulate bone cell growth. Carotenoids, found abundantly in fruit and vegetables, act as antioxidants in the body and it is this mechanism that may be protecting the bones from damage by naturally occurring unstable oxygen molecules in the body, known as free radicals.  Antioxidants may help to ‘quench’ the destructive free radical molecules and therefore protect against damage.  As nutrients, antioxidants are ingested in the diet and are then distributed via the blood into various parts of the body tissues, including the bones.  

The researchers involved in this latest study (2) looked at the potential effects on bone mineral density of overall and individual intake of several carotenoid compounds, including alpha-carotene, beta-carotene, beta-cryptoxanthin, lycopene, lutein and zeaxanthin.  The study scientists tracked the bone mineral density in the hip and spine of 213 men and 390 women over the course of four years.  They found that carotenoid intake was associated with some levels of protection against bone mineral density losses at the hip in men and at the spine in women.  The results suggest that carotenoids, especially lycopene, may be protective against bone loss in older adults.  Further studies are certainly needed but the evidence adds further weight to the mounting data which shows just how important fruits and vegetables are to the whole body, including our bones.

A diet rich in colourful fruits, vegetables will provide plentiful amounts of antioxidants.  Carotenoids are a family of over 700 naturally occurring yellow, red, orange and dark green pigments found in vegetables and fruits.  Good sources include carrots, sweet potatoes, tomatoes, squash, peppers, cantaloupe melons, nectarines, papaya, mango and dark green vegetables such as spinach, kale, watercress and asparagus.  Introducing a good mix of these fruits and vegetables on a regular basis in the diet will help keep carotenoid levels in the body high.

Absorption of carotenoids from foods into the body is greatly affected by fat.  Without a fat source carotenoids are not easily absorbed.  Fat acts as a carrier for these nutrients to allow them passage from the gut into our blood and bodily cells.  I am certainly not suggesting that you drown your vegetables or salads in gallons of oil, however, I am a firm believer in using small amounts of olive oil in dressings and cooking.  Including some nuts, seeds or olives in salads may also be helpful in order to gain maximum absorption of these important nutrients. 

If you are looking at carotenoid supplements, especially lycopene, look for those that contain an oil carrier, these will aid maximum absorption.  Of course fruits and vegetables contain far more than just carotenoids and a supplement cannot be seen as a substitute for good dietary habits, but if you feel that you do not get a good variety of vegetables and fruits in your daily diet you may wish to consider a supplement to help make up for any short-fall.

It is particularly important that young people look after their bone health, a balanced diet as well as exercise is vital in this respect.  Recently the National Osteoporosis Society (NOS) produced a press release and report regarding their findings that young people in the UK are endangering their health by not looking after their bones.  Prevention is the key to osteoporosis which affects up to three million people in the UK.

The NOS found that (3) that less than a quarter of people knew they should start looking after their bones before the age of 30, despite the fact that bone strength actually peaks during our 20s. Younger people need to ‘bank’ plenty of bone by the age of 30 as bones tend not to regenerate as quickly after that.  
• Almost half (49%) of young people (18-24 yrs) did not know there were any steps they could take to keep their bones healthy;
• More than half were unaware that exercise can help reduce the risk of osteoporosis;
• One in three did not know about the positive role diet can play.

Professor Roger Francis, Chair of the charity’s Medical Board, states(3):
 
“Our bones are living tissue, much like our skin. New bone replaces old throughout our lives. But the most crucial years are when we’re young as this is when the cells building new bone are most active. Until our mid 20s our bones are gaining density and strength. From our 30s onwards our bones gradually lose their density. The more we can build up our bones when we are young the better we can help to protect ourselves against osteoporosis and fragility fractures in later life.” (3)

Women are more at risk of developing osteoporosis since their bones are smaller and also more vulnerable to hormonal changes.  Being underweight, and having a low BMI (body mass index) is also a big risk factor.  Currently many girls and women are striving to reach a low bodyweight and achieve the size zero that is touted by so many celebrities.  The report found that only 21% of people knew that being underweight was a significant risk factor for osteoporosis development (3).

Encouraging young people to eat fruit and vegetables, as well as foods rich in calcium, magnesium and other minerals is very important for bone strength and development.  Please visit the National Osteoporosis Society website for more information about bone health. A very informative document about osteoporosis can be downloaded from the site and my post about eating for strong bones may also be of interest.

(1) New SA.  2003.  Intake of fruit and vegetables:implications for bone health.  Proc Nutr Soc.  62:889-899
(2) Sahni S et al.  2009.  Inverse association of carotenoid intakes with 4-y change in bone mineral density in elderly men and women: the Framingham Osteoporosis Study. Am J Clin Nutr 89: 416-424
(3) NOS press release

Written by Ani Kowal

On Monday I wrote generally about bone health.  Today I wanted to highlight the relatively recent research linking various B vitamins to bone health and strength. 

Scientists have been interested in preventing heart disease with the use of B vitamins for a while now.  This stems from the mounting research which suggests that elevated homocysteine levels are a risk factor for heart disease.

Homocysteine is produced when the amino acid (the building blocks of protein) methionine is broken down in the body.  Normal levels of homocysteine are important to help build and maintain body tissues, however elevated concentrations in the blood can be harmful and have been associated with an increased risk of heart disease and other disorders.  At normal levels homocystein can be converted in the body into a harmless substance called cystanthionine.  The conversion of homocysteine into this harmless substance depends upon various B vitamins  (B6, B12 and folic acid).  Having good levels of these B vitamins appears to be a very good way of preventing high homocysteine levels and low levels of B vitamins have been associated with raised homocysteine levels

Just recently research has been published (2,3) which suggests that B vitamins may also be important for the health of our bones and that elevated homocysteine levels may be implicated in bone deterioration.

In one study (2) the researchers wanted to examine the associations of blood plasma concentrations of folate, vitamin B12, vitamin B6, and homocysteine with bone loss and hip fracture risk in elderly men and women.  The study included a total of 1002 men and women with the average age of 75, their blood levels of B vitamins were measured at the start of the study and they were followed for 4 years.  Bone loss was associated with low vitamin B6 levels and low levels of vitamins B12 and B6 were associated with hip fracture risk.  The participants with high homocysteine levels also had a higher risk for hip fracture.

The study suggests that both low vitamin B status and high homocysteine levels may be a risk factor for hip fracture.  The authors of the study conclude that it is not entirely clear why or how B vitamins or homocysteine are related to bone health or fracture risk and that clinical trials with B vitamin supplements may help to provide more information. 

I find the results of the study very interesting as they highlight another area where nutrition is linked to health.  An overall healthy diet rich in a variety of unprocessed foods really does provide nutrients to all cells in the body.  Bones rely on essential nutrients as much as any other part of us!  All the cells in our body require regular, good supplies of the whole spectrum of nutrients.  A healthy diet really is important for so many reasons!

Vitamin B6 is found in foods like potatoes, bananas, beans and chickpeas, avocados, fish and poultry.  Vitamin B12 is found mainly in meat, fish and poultry.  Eggs and cheese also contain B12 as does brewer’s yeast.  Many vegetarians and vegans have very low intakes of this vital nutrient and may wish to consider a multi-B vitamin supplement.  Folic acid is found in beans, green vegetables and wholegrains.  If you decide you would like to take a vitamin B supplement I would always suggest a broad spectrum supplement that supplies adequate, but not megadose, levels of all of the B vitamins (not single nutrient supplements), these vitamins work best together as a team!

(1)The National Osteoporosis Society
(2)McLean R et al.  2008.  Plasma B Vitamins, Homocysteine, and Their Relation with Bone Loss and Hip Fracture in Elderly Men and Women.  J Clin Endocrinol Metab.  93: 2206-2212
(3)Cagnacci A et al.  2008.  Relation of folates, vitamin B12 and homocysteine to vertebral bone mineral density change in postmenopausal women. A five-year longitudinal evaluation. Bone.  42(2):314-20.

Written by Ani Kowal

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