The team's work represents the first comprehensive, evidence-supported dietary recommendations specifically for adults living with long-term constipation. The research also found that supplements such as psyllium fiber, certain probiotics, and magnesium oxide may provide additional relief.

In contrast, some popular methods often promoted for constipation management, including general "high-fiber diets" and senna supplements (a type of laxative), were found to lack convincing scientific support for effectiveness.

Backed by Strong Evidence and Expert Endorsement

The new guidelines were published in two major international journals, the Journal of Human Nutrition & Dietetics and Neurogastroenterology & Motility, and are endorsed by the British Dietetic Association (BDA). The aim is to transform how constipation is treated in clinical settings by providing healthcare professionals with clear, evidence-based tools. The guidelines also give individuals the ability to manage their condition more effectively through diet and hydration.

Constipation is a chronic condition that can seriously affect quality of life while adding to healthcare costs. Previous clinical recommendations have typically relied on increasing dietary fiber and fluid intake, an approach that researchers now say may be overly simplistic and outdated.

The Science Behind the New Guidelines

Unlike earlier guidance, the new recommendations draw on extensive systematic reviews and meta-analyses. Using the GRADE framework to evaluate evidence quality, an expert panel consisting of dietitians, a nutritionist, gastroenterologist, gut physiologist, and general practitioner examined data from more than 75 clinical trials. Their work resulted in 59 recommendations and the identification of 12 key areas for future research.

Dr. Eirini Dimidi, Reader in Nutritional Sciences at King's College London and lead author, explained: "Chronic constipation can have a huge impact on someone's day-to-day life. For the first time, we've provided direction on what dietary approaches could genuinely help, and which diet advice lacks evidence. Being able to improve this condition through dietary changes would allow people to self-manage their symptoms more and, hopefully, improve their quality of life."

Personalized Nutrition and Global Application

The guidelines also emphasize measurable outcomes, such as stool frequency and consistency, straining, and quality of life. This practical focus allows healthcare professionals to tailor dietary advice to individual symptom patterns. To support implementation, the researchers have created a clinician-friendly tool that can be used worldwide.

The review also revealed that while several foods and supplements appear effective, the quality of most existing research remains low. Many trials examined single interventions instead of comprehensive diet patterns, highlighting the need for more robust nutrition studies in constipation management.

Rethinking Fiber and Future Directions

Dr. Dimidi noted that although high-fiber diets are often promoted as beneficial for overall health, the new findings indicate limited evidence for their specific effectiveness in relieving constipation. "Eating a high fiber diet offers many benefits to overall health and has been a go-to recommendation for constipation," she said. "However, our guidelines found that there simply isn't enough evidence to suggest it actually works in constipation specifically. Instead, our research reveals some new dietary strategies that could indeed help patients. At the same time, we urgently need more high-quality trials to strengthen the evidence on what works and what doesn't."

Professor Kevin Whelan, senior author and Professor of Dietetics at King's College London, added: "This new guidance marks a promising step towards empowering health professionals and their patients to manage constipation through diet. This means that from now on that people suffering from constipation across the world can now receive up-to-date advice based upon the best available evidence in order to improve their symptoms and well-being. With continued research, it holds real potential to drive lasting improvements in quality of life."

Researchers found that taking 2,000 IU (international units, a standard measure for vitamins) of vitamin D daily helped preserve telomeres -- the tiny protective caps on our DNA that function like the plastic tips on shoelaces, preventing damage each time a cell divides.

Why Telomeres Matter

Each of our 46 chromosomes is capped with a telomere that becomes shorter every time a cell replicates. When these structures get too short, cells stop dividing and eventually die.

Shortened telomeres have been linked to major age-related diseases such as cancer, heart disease, and osteoarthritis. Factors like smoking, chronic stress, and depression can speed up this shortening process, while inflammation in the body also contributes to it.

More Than Just Bone Support

Most people know vitamin D for its essential role in building strong bones by helping the body absorb calcium. Children, teenagers, and those with darker skin or limited exposure to sunlight especially need sufficient levels to maintain bone strength.

Vitamin D also supports the immune system. Evidence shows that supplements can reduce the risk of respiratory infections, particularly in people who are deficient. Early research indicates that it might even help prevent autoimmune diseases such as rheumatoid arthritis, lupus, and multiple sclerosis, though more studies are needed to confirm this.

Because inflammation can accelerate telomere damage, vitamin D's anti-inflammatory properties may help explain its apparent protective effects.

Inside the Study

The recent research, conducted at Augusta University in the United States, followed 1,031 adults with an average age of 65 over five years. Participants were randomly assigned to take either 2,000 IU of vitamin D daily or a placebo. Their telomere lengths were measured at the beginning, after two years, and again after four years.

Results showed that those taking vitamin D maintained their telomeres by 140 base pairs compared with the placebo group. Considering that telomeres naturally shorten by roughly 460 base pairs over ten years, this preservation could be significant.

This study adds to previous research suggesting similar benefits. Diets rich in anti-inflammatory foods, such as the Mediterranean diet, have also been linked to longer telomeres.

What Scientists Still Don't Know

Despite the promising results, experts caution against jumping to conclusions. Some scientists note that overly long telomeres might actually raise the risk of certain diseases, suggesting there could be an ideal range that remains unclear.

There is also no universal agreement on the right dosage. The 2,000 IU used in the Augusta study is much higher than the recommended daily intake of 600 IU for adults under 70 and 800 IU for older adults. Other studies have suggested that even 400 IU per day may help prevent common infections such as colds.

Specialists emphasize that the optimal dose likely depends on individual factors like current vitamin D levels, diet, and how other nutrients interact in the body.

A Balanced Approach to Healthy Aging

While these findings are intriguing, researchers agree it's premature to rely on high-dose vitamin D supplements as an anti-aging strategy. The strongest evidence for maintaining long-term health still points to the basics: eating a balanced diet, exercising regularly, getting enough sleep, avoiding smoking, and managing stress -- all of which support telomere health naturally.

However, for those who are vitamin D deficient or at risk of bone problems, supplementation remains a well-supported and practical choice. As scientists continue to explore how aging works at the cellular level, vitamin D may turn out to be one important factor in a much larger picture of how to stay healthy as we grow older.