A combination of high-dose vitamin D, omega-3 fatty acids, and a simple at-home training program has been proven to reduce the risk of cancer by 61% in healthy people over age 70 years. These were the findings of an exploratory analysis in the international DO-HEALTH study, which observed more than 2000 elderly people over 3 years.
The risk of developing cancer increases as you get older. Aside from general precautions such as sun protection and not smoking, there are very few ways to protect yourself against cancerous diseases otherwise. “For middle-aged adults and the elderly, [measures to prevent against cancer] are largely limited nowadays to screenings and vaccinations,” explained the head of the DO-HEALTH study Heike Bischoff-Ferrari, MD, PhD, director of the Clinic for Geriatric Medicine at the University Hospital of Zurich, Switzerland.
Ambiguous Individual Effects
Vitamin D, omega-3 fatty acids, and physical exercise are all seen as promising candidates for cancer prevention. It has been suggested that vitamin D inhibits the growth of cancerous cells and that omega-3 fatty acids slow down the mutation of healthy cells into cancerous cells. In turn, physical exercise can improve immune function and reduce inflammation, which can also help to prevent cancer.
“As individual, preventive measures against cancer, taking vitamin D, taking omega-3 fatty acids, or exercising more have already been investigated in various studies, but these studies have not produced any clear results,” Valentin Goede, MD, head senior physician at the Geriatric Medicine Center and head of the Department for Geriatric Oncology at St Marien Hospital in Cologne, Germany, told Medscape Medical News. “Therefore, it’s interesting to see that it could be a combination of these measures that actually has some effect.”
An Exploratory Endpoint
The DO-HEALTH study was not originally created to find out whether a combination of high-dose vitamin D, omega-3 fatty acids, and a training program could protect against cancer. The primary aim was to investigate whether these measures affected blood pressure, physical performance, cognition, fractures, and infections in the elderly.
For this study, 2157 subjects from Switzerland, France, Germany, Austria, and Portugal were monitored for three years. They were at least 70 years old at the start of the study, had no severe comorbidities, were mobile, and were mentally fit.
Eight Study Groups
Participants were randomly assigned to the following eight groups to test the individual and combined benefits of the three measures:
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Group 1: 2000 IU vitamin D3 per day, 1 g omega-3 fatty acids per day, and a simple strength training program at home three times per week
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Group 2: Vitamin D3 plus omega-3 fatty acids
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Group 3: Vitamin D3 plus training program
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Group 4: Omega-3 fatty acids plus training program
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Group 5: Vitamin D3
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Group 6: Omega-3 fatty acids
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Group 7: Training program
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Group 8: Placebo
The subjects were called every 3 months to check on their adherence to the measures, among other things. In addition, standardized health and function assessments were performed onsite at the start of the study and then once per year.
A Positive Effect
“On the whole, this is a properly sized, high-quality study with a good design that can only be methodologically criticized on a few individual points at most,” said Goede. Nevertheless, it has had negative results regarding its primary endpoints. “These original results were already published in 2020 in JAMA, and no significant effects have been seen. The prevention of cancer was an exploratory endpoint, which is being dealt with subsequently.”
In doing so, the DO-HEALTH study showed a positive result for the first time. In particular, the exploratory analysis revealed that vitamin D3, omega-3 fatty acids, and the simple at-home training program were together associated with a lower risk of cancer in healthy and active people older than age 70 years.
Cancer Risk Reduction
There were 119 cases of cancerous disease reported in the study population over 3 years. Bischoff-Ferrari’s research team reported in the specialist journal Frontiers in Aging that each of the three measures in their own right slightly reduced the risk of cancer. “But the effect of the three measures was only statistically significant when in combination.” In Study Group 1, which received vitamin D and omega-3 fatty acids and also completed the training program, the cancer risk was 61% lower than in the placebo group.
After three years, the number needed to treat (NNT) to prevent a cancerous disease was 35 with all three measures combined. “Compared with the NNT we have otherwise in prophylactic geriatric medicine, this is a pretty good value,” said Goede.
Replication Required
“Novel cancer therapies aim to block the different ways in which cancer develops by combining various active substances. We have transferred this concept to cancer prevention,” said Bischoff-Ferrari. “Even though our results need to be replicated in an even larger, longer-term study, the three measures can be employed right away to reduce the high burden of cancerous diseases in elderly adults on the basis of their high safety and low cost.”
“It should be noted that after 3 years in a number of patients that is manageable for an epidemiological study, a reduction in cancer incidence could actually be observed with the combination of three preventive measures,” said Goede.
General Recommendation?
On the other hand, Goede agreed with the authors that the results need to be reproduced in a larger study with a longer follow-up period. “But I would still not actively encourage every healthy person over the age of 70 who comes to the medical practice simply for a checkup to follow these three preventive measures without being asked first,” he emphasized.
Aside from the replicability of the results, there are still some important questions to be answered. “For example, it was not possible in the DO-HEALTH study to show whether the three measures potentially only reduced the risk of certain cancerous diseases developing,” said Goede. They also offer no information about the optimal start of such measures or about whether the results can also be extended to older and sicker people.
“Should a fit person over the age of 70 ask me in a fairly direct manner whether there’s anything they can do to protect themselves against cancer, then I would refer to this study and definitely suggest these three measures. In this case, the evidence from this study would in turn be sufficient,” said Goede.
This article was translated from the Medscape German edition.
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