Medically reviewed by
Dr.Sanjana.V.B. Bhms. Dbrm.Cdn

Bone health, osteoporosis, falls &nutritional recommendations

  Bones make up the skeletal system of the human body. The adult human has two hundred and six bones. Bones account for the rigidity, structural outline of the body, erect posture and movement.  Bones protect the internal organs and other delicate structures within the body.

Structure of bones:

A bone is composed of calcified connective tissue. Ground substance and collagen fibers create a matrix that contains osteocytes. They are responsible for maintaining bone growth and density. Within the bone matrix both calcium and phosphate are abundantly stored, strengthening and densifying the structure. The inner core of bones (medulla) contains either red bone marrow (primary site of hematopoiesis) or is filled with yellow bone marrow filled with adipose tissue.

Functions of bones:

Bones and the skeleton play many important roles in the body, including:

· Bones store calcium and supply it to all the cells and organs of the body when dietary sources are insufficient.

· Bones support our body with muscle attachments, facilitating movement and use of our limbs, trunk, and head.

· Bones protect vital organs providing a rigid covering or enclosing it.

· Bones contain bone marrow, where all types of blood and bone cells are made.

Nutrition for Bone Health 

    Healthy bones and skeletal system are required for better health. Bones need all essential nutrients for its functions; such as protein, minerals, and vitamins to make and regenerate bone.

Calcium, phosphorus, zinc, and magnesium are most important minerals that should be obtained through diet. Vitamins A.D and K are also required for normal bone metabolism. Lack of these nutrients weakens bones and may lead to bone fractures.

 Calcium intake is vital to keep your bones healthy and adequate vitamin D to help your body absorb calcium.

Poor bone health from lack of nutrients can cause conditions such as rickets and osteoporosis and increase the risk of breaking a bone from a fall later in life [osteoporotic fracture ].

Food & nutrients to improve bone health 

Calcium

Calcium requirement for adults are 700mg / day. Taking a balanced diet may help you get adequate calcium.

Sources are:

·  Milk and other dairy foods

·  Green leafy vegetables, such as broccoli, cabbage and okra; but spinach is not a good choice.  Although spinach contains a lot of calcium, it also contains oxalate, which reduces  calcium absorption, and hence spinach is not considered as a good source of calcium.

·  Soya beans

·  Tofu

·  Calcium fortified soy milk

·   Nuts

·   Small fishes with bones, such as sardines and pilchards 

Vitamin D 

Adults need 10 micrograms (400 International Units or IU) of vitamin D a day. Vitamin D is essential for calcium absorption and therefore important for bone health.

It's difficult to obtain all the vitamin D through diet and the best source of vitamin D is sun light exposure of our skin. Vitamin is synthesized by the skin on getting exposure to sun. Ensure that you get enough day light, at least 15 minutes per day.

However, it is important for all to take a daily vitamin D supplement during the autumn and winter when it is difficult to make vitamin D from sunlight.

Risk groups for vitamin D deficiency

Those groups of people who are at risk of vitamin D deficiency should take a daily 10 microgram (400IU) vitamin D supplement all year round.

People who do not go often outdoors, from various reasons are at risk of Vitamin D deficiency. Wearing fully covered type of clothes even when at outdoors limit vitamin D synthesis from sun as skin is not exposed for sunlight to make vitamin D.

Dark skinned people also have risk for deficiency according to some research studies.

Menopausal women also are at risk for bone loss due to depleting estrogens. Women lose bone more rapidly for subsequent years since the menopause. Because their ovaries almost stop producing estrogen, which had a protective effect on bones until menopause.

However, there are no specific calcium or vitamin D recommendations for the menopause. Only a healthy balanced diet, including calcium, summer sunlight and vitamin D supplements [in case of lack of sunlight], will  suffice to slow down the rate of bone loss.

Vegans are also at risk of low vitamin D levels. Non-vegans get most of their calcium from dairy foods (milk, cheese and yoghurt), but pure vegans may have to get it from other foods such as fortified soya, rice and oat drinks, soya beans, calcium-set tofu, sesame seeds and tahini.

Other sources of vitamin D for vegans are:

o   Fortified fat spreads, breakfast cereals and plant-based drinks such as soya drink (with vitamin D added)

o   Vitamin D supplements 

During pregnancy and when breastfeeding, women who follow a vegan diet must ensure that they get enough vitamins and minerals for their child to develop healthily. Supplements are recommended in deficient group.

Long-term vitamin D deficiency has been associated with demineralization (loss of important minerals) of the bones. This is mainly because without adequate vitamin D, the body struggles to absorb calcium.

 Sources of vitamin D:

·  egg yolks

·  oily fish, such as salmon, sardines and mackerel

·  Vitamin D fortified foods

  A few other nutrients essential for bone health:

·  Magnesium

Magnesium is very important for bone health. Magnesium deficiency contributes to osteoporosis directly by acting on crystal formation and on bone cells and indirectly by impacting on the secretion and the activity of parathyroid hormone and by promoting low grade inflammation. Magnesium is available from leafy greens, legumes, and dairy[6]

· Omega-3 fatty acids

Omega-3 fatty acids (ω-3FAs) such as Docosahexaenoic acid (DHA) and Eicosapentanoic acid (EPA), are available in fish oil, which have larger health benefits against various diseases including cardiovascular, neurodegenerative, cancers and bone diseases.

 Research studies documented a preventive role of omega-3 fatty acids in pathological calcification like vascular calcification and micro calcification in cancer tissues.

Also, these fatty acids improve bone quality probably by preventing bone decay and enhancing bone mineralization.

 Natural sources of omega 3 fatty acids are flaxseed and fatty fish.

Supplementation of omega-3 fatty acids aids in bone preservation in elderly females at the risk of osteoporosis.

Administration of omega-3 fatty acid with chemotherapy will not only improve survival of cancer patients, but also improve the bone quality [10].

· Phosphorus

Phosphorus is an important nutrient for bone health. Most of the body’s phosphorus is found in bone mineral (approximately 85%), and the remaining 15% is distributed in soft tissues with about 1% in extracellular fluid.

Phosphorus deficiency results in rickets and stunted growth in children and osteomalcia in adults.

However, dietary phosphorus deficiency is very rare in humans, as naturally phosphorus is available in a variety of common foods and body can easily absorb it. Low phosphorus levels happen only in conditions such as starvation, refeeding syndrome etc. Thus, most cases of phosphorus deficiency result from a defect in renal reabsorption of phosphate, a condition associated with kidney diseases.

Phosphorus is present in foods in naturally-occurring forms in meats, nuts, seeds, legumes, dairy foods, and grains, as well as in inorganic phosphate additives that are used for a variety of purposes in food processing [13].

·  Zinc

Bone growth retardation is a common in various conditions associated with dietary zinc deficiency. So zinc has been considered as an important mineral promoting bone health.

Bone zinc content has been shown to decrease in aging and postmenopausal conditions, suggesting its role in bone disorder.

 Zinc has been demonstrated to have a stimulatory effect on osteoblastic bone formation and mineralization;

 Zinc directly activates aminoacyl-tRNA synthetase, a rate-limiting enzyme at translational process of protein synthesis, in the cells, and it stimulates cellular protein synthesis.[12]

Natural sources of zinc are beans, eggs, meat, and sea foods.

· Potassium

Potassium has vital role in maintaining bone health.

Dietary potassium may neutralize acid load and reduce calcium loss from the bone, leading to beneficial effect on bone mineral density.

Dietary potassium intake is associated with improved bone mineral density in older men and postmenopausal women[11].

Potassium is found chiefly in fruits, vegetables, lentils, dairy, and meat

·  Vitamin C

Vitamin C is important for bone formation. Cell studies shows that vitamin C was able to induce osteoblast and osteoclast formation. However, high-dose vitamin C might increase oxidative stress and subsequently lead to cell death.

Vitamin C-deficient animals showed impaired bone health due to increased osteoclast formation and decreased bone formation [7].

A balanced diet with vitamin C is recommended for bone health.

Vitamin C is abundant in citrus and other fruits and vegetables

·  Vitamin K

It is an essential vitamin for bone health, taking part in the carboxylation of many bone-related proteins, regulating genetic transcription of osteoblastic markers, and regulating bone reabsorption.

Most studies find that low serum vitamin K1 concentrations, high levels of undercarboxylated osteocalcin (ucOC), and low dietary intake of both K1 and K2 are associated with a higher risk of fracture and lower bone mineral density [BMD] [8].

Studies exploring the relationship between vitamin K supplementation and fracture risk also find that the risk of fracture is reduced with supplements, but further extensive research studies are necessary to elucidate the role of supplements.

Vitamin K  is available from natural sources.

Vitamin K may be obtained from green vegetables, vegetable oils, meat, cheese, and eggs.

·  Folates

Folates are b group vitamins.it is believed that they have some role in bone health too.

Serum concentration of homocysteine is inversely related to  vitamin B12 and folic acid levels [9].

During menopause the serum level of homocysteine is increased and  high levels of homocytein is linked with risk of fracture.Folate supplementation may modify the serum concentration of homocysteine, and can affect fracture risk.

The exact role of homocysteine level and folic acid supplementation in regulation of bone metabolism is yet to be elucidated.

Natural sources of folates are fruits, vegetables, nuts, beans, peas, and beef liver.

Folic acid  is a vitamin closely linked to women’s health at every phase of life.

FAQ- FREQUENTLY ASKED QUESTIONS ON BONE NUTRITION

Does excess vitamin A intake increase the risk for bone fracture?

Some research studies have suggested a link between too much vitamin A intake and an increased risk of bone fractures. Regular consumption of liver and retinol supplements pose the risk and it needs to be restricted.

People at risk of osteoporosis, such as postmenopausal women and older people, are advised to limit their retinol intake to no more than 1.5mg (1,500 micrograms) a day by eating less liver and liver products.

 How do phytates in plants  affect bone health?

Calcium absorption is interfered by phytates. Beans (Legumes) contain calcium, magnesium, fiber and other nutrients, they are also high in substances called phytates. Phytates interfere with your body’s ability to absorb the calcium, contained in beans.  Soaking beans in water for several hours and then cooking them in fresh water may help to reduce phytates.

How does Sodium intake from processed foods affect bone health ?

Avoid excessive use of processed foods, canned foods and salt in your regular diet. Always have a look at the Nutrition Facts label to know the contents and their levels. If it lists 20% or more of salt for the % Daily Value, it is high in sodium. Aim to get no more than 2,300 mg of sodium per day.

Dietary consumptions of sodium chloride (salt) and excess protein are known to increase urinary calcium excretion. Therefore, a high salt intake is considered one of the major risk factor for osteoporosis due to increased calcium loss through urine.

In addition ,low calcium intakes may contribute to a compensatory response leading to increased bone remodeling and bone loss, which might be  continued by an increase in dietary salt consumption.

Sustained low sodium levels in blood also are not only potentially harmful for bone health but also seems to increase the risk of cardiovascular diseases and sometimes deaths.[5]

Do spinach and other foods with oxalates impede calcium absorption ?

Human body cannot absorb calcium well from foods that are high in oxalates such as spinach, rhubarb, beet greens and certain beans. Although these foods contain other healthy nutrients, they just shouldn’t be considered as sources of calcium.

How does wheat Bran reduce calcium absorption?

 Wheat bran contains high levels of phytates which can prevent your body from absorbing calcium. However,100% wheat bran is the only food that appears to reduce the absorption of calcium intake from other foods taken simultaneously. If you consume milk and 100% wheat bran cereal together, your body can absorb some, but not all, of the calcium from the milk.

 If you are on calcium supplements, you may take your calcium tablets a few hours before or after eating 100% wheat bran. 

 Does alcohol intake affect  bone health ?

Drinking alcohol excessively and regularly can lead to bone loss.

Human and animal studies clearly shows that chronic, heavy alcohol consumption compromises bone health and increases the risk of osteoporosis.

 Heavy alcohol intake decreases bone density and weakens bones’ mechanical properties. These effects are seen predominantly in young people, but chronic alcohol use in adulthood can also harm bone health.

Further, animal studies suggest that bones do not overcome the damaging effects of early chronic alcohol intake, even when alcohol use is discontinued or withdrawn [4].

The effect of moderate alcohol consumption on bone health is less clear.

What is the effect of Caffeine on bones ?

Coffee, tea and soft drinks contain caffeine, which may decrease calcium absorption and contribute to bone loss. Choose these drinks in moderation.

Drinking more than three cups of coffee every day may interfere with calcium absorption and cause bone loss.

Some studies suggest that colas, but not other soft drinks, are linked with bone loss. Further extensive studies are needed in this area to clearly understand the impact of soft drinks on bones

 

References

 
1.https://www.nhs.uk/live-well/bone-health/food-for-strong-bones/
2. https://orthoinfo.aaos.org/en/staying-healthy/bone-health-basics/
3. https://www.kenhub.com/en/library/anatomy/bones
4. https://pubs.niaaa.nih.gov/publications/arh26-4/292-298.htm#:~:text=In%20particular%2C%20heavy%20alcohol%20use,can%20also%20harm%20bone%20health.
5. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6140170/#:~:text=Dietary%20consumptions%20of%20sodium%20chloride,to%20increase%20urinary%20calcium%20excretion.&text=Therefore%2C%20a%20high%20salt%20intake,osteoporosis%20due%20to%20increased%20calciuria.

6. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3775240/#:~:text=Magnesium%20deficiency%20contributes%20to%20osteoporosis,by%20promoting%20low%20grade%20inflammation.
 
7. https://pubmed.ncbi.nlm.nih.gov/26343111/#:~:text=Background%3A%20Vitamin%20C%2C%20traditionally%20associated,radicals%20detrimental%20to%20bone%20health.
8. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6955144/#:~:text=Although%20known%20for%20its%20importance,markers%2C%20and%20regulating%20bone%20reabsorption.
9. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4172791/
 
10. https://pubmed.ncbi.nlm.nih.gov/32548903/
11. https://pubmed.ncbi.nlm.nih.gov/28093633/#:~:text=Abstract,older%20men%20and%20postmenopausal%20women.
12https://pubmed.ncbi.nlm.nih.gov/20035439/
13.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5693714/