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Rickets is the archetypical disease of vitamin D deficiency in children. It was ubiquitous in the industrialised cities of the UK. Theobald Palm finished studying medicine at the University of Edinburgh in the 1800s. The son of Scottish Presbyterian missionaries, he was born in Ceylon, now Sir Lanka. Following medical school, began medical missionary work in Japan. There he noticed that rickets was virtually absent. Had Palm remained a medical missionary, nothing might have transpired. But he returned to the UK and there he noted an epidemic of rickets in large towns that had limited sunlight exposure. As with many groundbreaking medical discoveries, for many years, Palm’s observations were largely ignored. Ultimately, following Palm’s shrewd observations, it was recognised that the production of vitamin D in the body was contingent on exposure to UVB.

What is Vitamin D?

Perhaps surprisingly, vitamin D is not a vitamin at all. It is actually a prohormone involved in the tight regulation of calcium and phosphate levels. Hence, it is vital for healthy bones, effective muscle contraction, immune function and other important cellular functions.

So vitamin D has long been celebrated for its role in bone health. Yet its influence on broader health outcomes is garnering increasing attention. This is particularly the case in preventing early-onset colorectal cancer (CRC). Recent research leveraging the extensive UK Biobank data provided compelling insights into how vitamin D might play a pivotal role in warding off CRC, especially among adults under 50. The UK biobank is a huge repository of biomedical data that can be accessed by medical researchers worldwide.

A Closer Look at the Research

The study in question delved into the health records of 236,382 Korean adults. It tracked a range of health metrics, including serum 25-hydroxyvitamin D [25(OH)D] levels. The follow-up period averaged 6.5 years. In this time the researchers discovered that higher levels of vitamin D were associated with significantly reduced risks of developing colorectal cancer. These were findings that held strong even after adjusting for numerous potential confounders.

Vitamin D and Its Protective Mechanisms

What’s particularly intriguing about this study is its implications for both young and older adults. For those under 50, maintaining higher levels of vitamin D was linked with a nearly 60% reduction in CRC risk. This protective effect, although slightly attenuated, was also evident in the older cohort. Hence, the study suggests that vitamin D’s benefits span age groups.

The biological underpinnings of vitamin D’s protective effects relate to its regulatory role of our DNA. Vitamin D helps orchestrate the expression of several genes. This includes those involved in cell growth and repair. Such mechanisms are vital for cancer prevention. Essentially, vitamin D acts much like a fastidious manager within a complex system. It ensures that everything runs smoothly and efficiently. Importantly, it also shuts down potential problems before they escalate.

Practical Implications and Lifestyle Integration

Given the association between vitamin D levels and reduced CRC risk, particularly among younger adults, there is a strong case for assessing your vitamin D status. This is especially the case for those with a family history of colorectal cancer. Here’s how you can incorporate this knowledge into a proactive health strategy:

1. Regular Screening: Consider regular checks of your vitamin D levels as part of your routine health assessments. This is especially pertinent during the darker months. It’s also particularly important if your lifestyle limits sun exposure.
2. Mindful Supplementation: If your vitamin D levels are found to be lacking, supplementation could be a key strategy. It’s a simple, safe way to potentially reduce your risk of serious health issues like colorectal cancer.
3. Dietary Sources: Sunlight is the primary source of vitamin D. However, incorporating vitamin D-rich foods like fatty fish, fortified dairy products, and certain mushrooms can also help boost your levels.
4. Understanding Your Genetics: The study highlighted that genetic factors might influence how vitamin D impacts us. Engaging with genetic screening could provide personalised insights, tailoring your approach to supplementation.

A Final Thought

We have to navigate a plethora of dietary advice and health strategies. Understanding the nuanced role of nutrients like vitamin D in disease prevention is crucial. This isn’t just about taking a supplement. It’s also about integrating a scientifically backed approach into your daily routine for long-term health benefits.

Theobald Palm extolled the virtues not only of sunlight. He urged the use of open spaces, especially playgrounds for children. This is something we should take to heart. A vitamin D supplement may be beneficial. But the benefits of safe sun exposure, movement and nature compound to maximise health benefits. 

Dr J Hugh Coyne 

Private GP 

Parsons Green