Vitamin D is essential for bone health, immune function and overall wellbeing. And it becomes even more crucial as we age.

New guidelines from the international Endocrine Society recommend people aged 75 and over should consider taking vitamin D supplements.

But why is vitamin D so important for older adults? And how much should they take?

Young people get most vitamin D from the sun

In Australia, it is possible for most people under 75 to get enough vitamin D from the sun throughout the year. For those who live in the top half of Australia – and for all of us during summer – we only need to have skin exposed to the sun for a few minutes on most days.

The body can only produce a certain amount of vitamin D at a time. So staying in the sun any longer than needed is not going to help increase your vitamin D levels, while it will increase your risk of skin cancer.

But it’s difficult for people aged over 75 to get enough vitamin D from a few minutes of sunshine, so the Endocrine Society recommends people get 800 IU (international units) of vitamin D a day from food or supplements.

Why you need more as you age

This is higher than the recommendation for younger adults, reflecting the increased needs and reduced ability of older bodies to produce and absorb vitamin D.

Overall, older adults also tend to have less exposure to sunlight, which is the primary source of natural vitamin D production. Older adults may spend more time indoors and wear more clothing when outdoors.

As we age, our skin also becomes less efficient at synthesising vitamin D from sunlight.

The kidneys and the liver, which help convert vitamin D into its active form, also lose some of their efficiency with age. This makes it harder for the body to maintain adequate levels of the vitamin.

All of this combined means older adults need more vitamin D.

Deficiency is common in older adults

Despite their higher needs for vitamin D, people over 75 may not get enough of it.

Studies have shown one in five older adults in Australia have vitamin D deficiency.

In higher-latitude parts of the world, such as the United Kingdom, almost half don’t reach sufficient levels.

This increased risk of deficiency is partly due to lifestyle factors, such as spending less time outdoors and insufficient dietary intakes of vitamin D.

It’s difficult to get enough vitamin D from food alone. Oily fish, eggs and some mushrooms are good sources of vitamin D, but few other foods contain much of the vitamin. While foods can be fortified with the vitamin D (margarine, some milk and cereals), these may not be readily available or be consumed in sufficient amounts to make a difference.

In some countries such as the United States, most of the dietary vitamin D comes from fortified products. However, in Australia, dietary intakes of vitamin D are typically very low because only a few foods are fortified with it.

Why vitamin D is so important as we age

Vitamin D helps the body absorb calcium, which is essential for maintaining bone density and strength. As we age, our bones become more fragile, increasing the risk of fractures and conditions like osteoporosis.

Keeping bones healthy is crucial. Studies have shown older people hospitalised with hip fractures are 3.5 times more likely to die in the next 12 months compared to people who aren’t injured.

Vitamin D may also help lower the risk of respiratory infections, which can be more serious in this age group.

There is also emerging evidence for other potential benefits, including better brain health. However, this requires more research.

According to the society’s systematic review, which summarises evidence from randomised controlled trials of vitamin D supplementation in humans, there is moderate evidence to suggest vitamin D supplementation can lower the risk of premature death.

The society estimates supplements can prevent six deaths per 1,000 people. When considering the uncertainty in the available evidence, the actual number could range from as many as 11 fewer deaths to no benefit at all.

Should we get our vitamin D levels tested?

The Endocrine Society’s guidelines suggest routine blood tests to measure vitamin D levels are not necessary for most healthy people over 75.

There is no clear evidence that regular testing provides significant benefits, unless the person has a specific medical condition that affects vitamin D metabolism, such as kidney disease or certain bone disorders.

Routine testing can also be expensive and inconvenient.

In most cases, the recommended approach to over-75s is to consider a daily supplement, without the need for testing.

You can also try to boost your vitamin D by adding fortified foods to your diet, which might lower the dose you need from supplementation.

Even if you’re getting a few minutes of sunlight a day, a daily vitamin D is still recommended.

Elina Hypponen, Professor of Nutritional and Genetic Epidemiology, University of South Australia and Joshua Sutherland, PhD Candidate – Nutrition and Genetic Epidemiology, University of South Australia

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Children with traumatic experiences in their early lives have a higher risk of obesity. But as our new research shows, this risk can be reduced through positive experiences.

Childhood traumatic experiences are alarmingly common. Our analysis of data from nearly 5,000 children in the Growing Up in New Zealand study revealed almost nine out of ten (87%) faced at least one significant source of trauma by the time they were eight years old. Multiple adverse experiences were also prevalent, with one in three children (32%) experiencing at least three traumatic events.

Childhood trauma includes a range of experiences such as physical and emotional abuse, peer bullying and exposure to domestic violence. It also includes parental substance abuse, mental illness, incarceration, separation or divorce and ethnic discrimination.

We found children from financially disadvantaged households and Māori and Pasifika had the highest prevalence of nearly all types of adverse experiences, as well as higher overall numbers of adversities.

The consequences of these experiences were far-reaching. Children who experienced at least one adverse event were twice as likely to be obese by age eight. The risk increased with the number of traumatic experiences. Children with four or more adverse experiences were nearly three times more likely to be obese.

Notably, certain traumatic experiences (including physical abuse and parental domestic violence) related more strongly to obesity than others. This highlights the strong connection between early-life adversity and physical health outcomes.

Connecting trauma to obesity

One potential explanation could be that the accumulation of early stress in children’s family, school and social environments is associated with greater psychological distress. This in turn makes children more likely to adopt unhealthy weight-related behaviours.

This includes consuming excessive high-calorie “comfort” foods such as fast food and sugary drinks, inadequate intake of nutritious foods, poor sleep, excessive screen time and physical inactivity. In our research, children who experienced adverse events were more likely to adopt these unhealthy behaviours. These, in turn, were associated with a higher risk of obesity.

Despite these challenges, our research also explored a promising area: the protective and mitigating effects of positive experiences.

We defined positive experiences as:

• parents in a committed relationship
• mothers interacting well with their children
• mothers involved in social groups
• children engaged in enriching experiences and activities such as visiting libraries or museums and participating in sports and community events
• children living in households with routines and rules, including those regulating bedtime, screen time and mealtimes
• children attending effective early childhood education.

The findings were encouraging. Children with more positive experiences were significantly less likely to be obese by age eight.

For example, those with five or six positive experiences were 60% less likely to be overweight or obese compared to children with zero or one positive experience. Even two positive experiences reduced the likelihood by 25%.

How positive experiences counteract trauma

Positive experiences can help mitigate the negative effects of childhood trauma. But a minimum of four positive experiences was required to significantly counteract the impact of adverse events.

While nearly half (48%) of the study participants had at least four positive experiences, a concerning proportion (more than one in ten children) reported zero or only one positive experience.

The implications are clear. Traditional weight-loss programmes focused solely on changing behaviours are not enough to tackle childhood obesity. To create lasting change, we must also address the social environments, life experiences and emotional scars of early trauma shaping children’s lives.

Fostering positive experiences is a vital part of this holistic approach. These experiences not only help protect children from the harmful effects of adversity but also promote their overall physical and mental wellbeing. This isn’t just about preventing obesity – it’s about giving children the foundation to thrive and reach their full potential.

Creating supportive environments for vulnerable children

Policymakers, schools and families all have a role to play. Community-based programmes, such as after-school activities, healthy relationship initiatives and mental health services should be prioritised to support vulnerable families.

Trauma-informed care is crucial, particularly for children from disadvantaged households who face higher levels of adversity and fewer positive experiences. Trauma-informed approaches are especially crucial for addressing the effects of domestic violence and other adverse childhood experiences.

Comprehensive strategies should prioritise both safety and emotional healing by equipping families with tools to create safe, nurturing environments and providing access to mental health services and community support initiatives.

At the family level, parents can establish stable routines, participate in social networks and engage children in enriching activities. Schools and early-childhood education providers also play a key role in fostering supportive environments that help children build resilience and recover from trauma.

Policymakers should invest in resources that promote positive experiences across communities, addressing inequalities that leave some children more vulnerable than others. By creating nurturing environments, we can counterbalance the impacts of trauma and help children lead healthier, more fulfilling lives.

When positive experiences outweigh negative ones, children have a far greater chance of thriving – physically, emotionally and socially.

Ladan Hashemi, Senior Research Fellow in Health Sciences, University of Auckland, Waipapa Taumata Rau

This article is republished from The Conversation under a Creative Commons license. Read the original article.