Staying active in older age: Week 6 – Keeping our bones healthy during lockdown

As we get older, maintaining bone health becomes a top priority. Having healthy bones reduces our risk for osteoporosis and also helps us to stay active because bones provide a structure for our muscles and tendons. Having healthy bones also reduces the risk of them breaking or fracturing them if we fall. And importantly, our bones play a key role in supporting our responses to viruses and infections, as many of the blood cells that play a role in immune function are produced in the bone marrow, the spongy tissue inside bones.

Having to shield and stay indoors and the inability to spend time outdoors in the sunlight is one of the main challenges of lock-down. This is because one of the main nutrients to support bone health is vitamin D, the “sunshine vitamin”. The main source of vitamin D is actually our own bodies – we can make it when our skin is exposed to sunlight. Getting adequate exposure to sunlight is important, as there are very few foods that naturally contain vitamin D.

Many people who live in the UK, have poor vitamin D status. This is because in the winter months (October through March), the sun is not strong enough to stimulate our bodies to produce vitamin D. And of course, getting adequate sun exposure may not be possible for people who are self-isolating and/or shielding during the lockdown.¹

The most recent expert guidance for safe sunlight exposure is to spend about 10 minutes around lunch-time for light-skinned people, and about 25 minutes for people with darker skin¹ in the sun without using sunscreen. These short time exposures will help to avoid sunburn. Exposing your face, hands, feet, and/or forearms is enough, in the garden, on a balcony or just standing at the door in the sun is fine.

Anyone who really can’t get out and expose their skin to the sun should take a vitamin D supplement. In the UK, it is advised that people take 400IU of vitamin D daily¹. There is no evidence that taking high amounts of vitamin D will treat or prevent COVID-19. In fact, taking high doses (higher than 4000IU per day) can be dangerous, particularly in people with reduced kidney function. If you are concerned about your vitamin D status, contact your healthcare professional to discuss the best supplement to take.

Another challenge during lockdown is difficulty buying foods and drinks that contain many of the nutrients necessary for good bone health. The table below includes an overview of the key nutrients we need to support bone health, and common foods that contain them.²

 

Nutrient	Food Sources	Role in supporting bone health
Calcium:	Animal-based: Milk, yogurt, cheese, sardines Plant-based: -Dark green leafy vegetables (spinach, kale) -Calcium-fortified juices and milk alternatives	-Calcium is the main component of bone
Vitamin D -Very limited amounts found in foods	Animal-based: Oily fish (salmon, mackerel, sardines, pilchards, anchovies), eggs, dairy products fortified with vitamin D Plant-based: Breakfast cereals fortified with vitamin D Other sources: We create our own Vitamin D when our skin is exposed to sunlight. People who do not go outside much or who do not expose their skin to the sun need to take a supplement (a tablet or spray- see information below)	-Enhances the absorption of calcium and phosphorus in the foods and beverages we consume -Communicates with our kidneys to make sure we control healthy levels of calcium in our bodies
Vitamin K	Animal-based: None – although the bacteria in our colon produces vitamin K, which we then absorb and use Plant-based: Dark green leafy vegetables (spinach, kale, turnip greens, brussels sprouts)	-Helps to make specific proteins that build and repair bone
Phosphorus	Animal-based: Milk, yogurt, cheese, poultry Plant-based: Soy milk, tofu, lentils, black beans, nuts (particularly almonds, peanuts and peanut butter)	-One of the main components of bone (in addition to calcium)
Magnesium	Animal-based: Yogurt, fish (salmon, halibut), chicken breast Plant-based: Dark green leafy vegetables (spinach, kale), whole grains, soymilk, black beans, kidney beans, potatoes, peanut butter	-An important component of bone -Supports vitamin D to do its role in maintaining bone health
Fluoride	Animal-based: Fish, shellfish Plant-based: Pulses, lentils, whole grains, tea, tap water	-An important component of bone -Enhances the strength and health of teeth and fights the bacteria that cause tooth decay

The positive news is that eating a wide variety of these foods will help ensure you are getting the nutrients needed to support bone health.

So by combining a good diet, plenty of exercise and a little sunbathing we can make sure that our bones are as strong and healthy as possible, even during lockdown.

Our next blog will look into the benefits of exercise on our mental health, but in the meantime KEEP MOVING and STAY SAFE.

Professor Janice L. Thompson
Dr Janet Withall, REACT Trial Manager, University of Bath
Dr Afroditi Stathi, REACT Chief Investigator, University of Birmingham
Dr Jolanthe de Koning, REACT Research Associate, University of Bath
Dr Pete Ladlow, UK Defence Medical Rehabilitation Centre

References:

¹Lanham-New, SA et al. (2020). Vitamin D and SARS-CoV-2 virus/COVID-19 disease. BMJ Nutrition, Prevention & Health. doi:10.1136/bmjnph-2020-000089.

²Thompson, J et al. (2020). The Science of Nutrition. 5^th Edition. San Franciso:Pearson Education.