The dairy in our diets is frequently promoted as a vital bone-builder, so is a vegan diet bad for bone health?
Young people are ditching meat and dairy ‘in record numbers’, according to recent data from a YouGov survey commissioned by the Eating Better Alliance . It estimated that 25 % of 18-year-olds are either vegetarian or vegan and with increasing concern about environmental issues, these numbers seem set to increase.
Building healthy bones is extremely important.
90% of our bone mass is built by the age of 16, and once you reach 30 years of age, you will have achieved peak bone mass. If not enough bone mass is created during this time, you have an increased risk of developing fragile bones that break easily, a condition called osteoporosis.
As more and more young people adopt a vegan lifestyle, should we be concerned that they are increasing their risk of developing osteoporosis in later life?
This article reviews the evidence to see whether these concerns might be valid. We will look at how bones are made, the science behind diet and bone health, review studies comparing the bone health of vegans to non-vegans, and outline ways to ensure that your vegan diet contains plenty of bone-building, plant-based alternatives.
How Are Bones Made?
Bone is a living, growing tissue. There is a constant turnover, with new bone being added and old bone being removed.
The main component of your bones is a protein called collagen. This provides a soft, flexible framework. Calcium phosphate is then added to the collagen to make your bones hard, strong and stress-proof.
Childhood and teenage are our main bone-building years. During this time new bone is added to the skeleton faster than old bone is removed. As a result, bones become larger and denser.
For most people, bone formation continues at a faster pace than removal until bone mass peaks at the age of 30.
As we age we lose bone mass because the rate of bone removal is faster than the rate of replacement. This can result in osteopenia (low bone mass) and osteoporosis (brittle bones), particularly if you did not reach your maximum peak bone mass during your bone-building years.
Women are more likely to develop osteoporosis. They generally have smaller bones than men have and falling oestrogen levels after the menopause causes more rapid loss of bone tissue.
Diet and Bone Health
Because old bone tissue is constantly broken down and replaced, it’s important to consume key ingredients daily to protect bone structure and strength.
Calcium is the more important mineral for bone health.
Calcium requirements vary depending on age:
Adults require 700mg/day; 7-10 years olds – 550mg calcium/day; 11-18 year olds – 800mg calcium/day (female), 1000mg calcium/day (male)
The amount of calcium your body actually absorbs can vary greatly. Spreading your calcium intake throughout the day will optimize absorption.
50% of bone is made of protein, so having sufficient protein in your diet is important for bone health.
Research has shown that low protein intake may affect rates of bone formation and breakdown in a negative way. It also decreases calcium absorption.
High protein intake can help protect bone health during ageing. Research suggests that older women, in particular, appear to have higher bone density and a lower risk of fractures when they consume higher amounts of protein.
Vitamin D and K
Getting adequate amounts of vitamin D and K is essential as they both play important roles in building strong bones.
Vitamin D helps your body absorb calcium. Studies have shown that children and adults with low vitamin D levels tend to have lower bone density and are more at risk for bone loss than people who get enough.
Vitamin D deficiency is very common and is a particular problem for those following a vegan diet.
Vitamin K supports bone health by modifying a protein called osteocalcin which helps bone formation. Studies have shown that the modified osteocalcin binds calcium more strongly to bone tissue and increases bone density.
A diet high in vegetables has been shown to help create healthy bones
Research has linked a high intake of green and yellow vegetables to an increase in bone density. A three-month study also showed reduced bone turnover (and therefore risk of osteoporosis) in women who consumed high quantities of broccoli, cabbage and parsley.
Vegetables are also a great source of vitamin C. Research has shown vitamin C stimulates the production of bone-forming cells and may protect bone cells from damage.
Green leafy vegetables, such as broccoli, cabbage and okra are also good sources of calcium. Spinach should be consumed in moderation. It contains oxalic acid, which reduces calcium absorption.
Are Vegan Diets Bad For Bone Health?
Research has indicated that people who follow vegan or vegetarian diets have lower intakes of dietary protein and lower BMIs than meat eaters. Vegans may also have significantly lower intakes of calcium.
In the last couple of decades there has been significant research in Europe to find out how these dietary differences affect bone health and fracture risk.
In a large UK based study, scientists found that vegans with lower calcium and protein intakes had, on average, a 43% higher risk of bone fractures than meat eaters. The biggest difference was found in the rate of hip fractures, where the risk in vegans was 2.3 times higher than in people who ate meat.
However, once body mass index (BMI), dietary calcium and protein intakes were taken into account the increased risk of fractures in these groups almost disappeared.
It is also worth noting that 75% of the study participants were European women. Further research is needed to explore differences in risk by sex and ethnicity.
Can I Plan a Vegan Diet to Promote Bone Health?
The research suggests that vegan diets low in calcium, vitamin D or protein could lead to poor bone health.
In the UK, the particular importance of dairy as a source of some of these nutrients for children is emphasized by the NHS (2018).
Parents are advised not to cut out dairy from their children’s diet without consulting a doctor first.
However, with the right planning you and your children can get everything you need to support good bone health whilst following a vegan diet.
Focus on ensuring you have adequate levels of calcium (and Vitamin D to help absorption), protein and also make sure you maintain a healthy BMI.
Calcium is key, so it’s essential that calcium requirements are met, particularly for children. Plant-based milk and dairy substitutes fortified with calcium and vitamin D are a good choice.
Questions have been raised about the bioavailability of calcium in some of these products, but fortified soy based milk substitutes have been shown to contain similar levels of bioavailable calcium as cow’s milk
Almonds, calcium-set tofu, beans and green leafy vegetables are also good sources of calcium, and should be regularly included in your diet. However it is worth noting that high quantities of fibre, phytates and oxalates present in some vegetables can limit the bioavailability of calcium.
There are plenty of vegetable based protein-rich foods suitable for a vegan diet. Aim to include three portions of protein per day.
Although many plant-based protein sources are regarded to be incomplete, including a good mix of pulses, beans and lentils along with grains such as quinoa and nuts will ensure you get a full range of the required amino acids.
There are also many vegan protein bars which contain essential amino acids.
Foods rich in vitamin D are limited and vitamin D deficiency can be a problem among vegans and meat eaters alike.
Fortified foods and sun exposure are good sources of this essential nutrient, but you should also consider taking a vitamin D2 or D3 supplement.
Vegans do need to take particular care to protect their bone health, but it is important not to forget that adopting a vegan lifestyle can potentially reducing the risk of other chronic health problems such as obesity, type 2 diabetes, cancer and cardio vascular disease.