Category: Diet and Nutrition

Categories : Diet and NutritionTags :

Black Coffee Linked to Lower Risk of All-cause Mortality

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While you’re probably not pouring your morning cup for the long-term health benefits, coffee consumption has been linked to lower risk of mortality. In a new observational study, researchers from Tufts University found the association between coffee consumption and mortality risk changes with the amount of sweeteners and saturated fat added to the beverage. 

The study, published online in The Journal of Nutrition, found that consumption of 1-2 cups of caffeinated coffee per day was linked to a lower risk of death from all causes and death from cardiovascular disease. Black coffee and coffee with low levels of added sugar and saturated fat were associated with a 14% lower risk of all-cause mortality as compared to no coffee consumption. The same link was not observed for coffee with high amounts of added sugar and saturated fat. 

“Coffee is among the most-consumed beverages in the world, and with nearly half of American adults reporting drinking at least one cup per day, it’s important for us to know what it might mean for health,” said study senior author Professor Fang Fang Zhang at the Gerald J. and Dorothy R. Friedman School of Nutrition Science and Policy. “The health benefits of coffee might be attributable to its bioactive compounds, but our results suggest that the addition of sugar and saturated fat may reduce the mortality benefits.” 

The study analysed data from nine consecutive cycles of the National Health and Nutrition Examination Survey (NHANES) from 1999 to 2018, linked to National Death Index Mortality Data. The study included a nationally representative sample of 46 000 adults aged 20 years and older who completed valid first-day 24-hour dietary recalls. Coffee consumption was categorised by type (caffeinated or decaffeinated), sugar, and saturated fat content. Mortality outcomes included all-cause, cancer, and cardiovascular disease. Low added sugar (from granulated sugar, honey, and syrup) was defined as under 5% of the Daily Value, which is 2.5 grams per 8-ounce [250mL] cup or approximately half a teaspoon of sugar. Low saturated fat (from milk, cream, and half-and-half) was defined as 5% of the Daily Value, or 1 gram per 250mL cup or the equivalent of 5 tablespoons of 2% milk, 1 tablespoon of light cream, or 1 tablespoon of half-and-half. 

In the study, consumption of at least one cup per day was associated with a 16% lower risk of all-cause mortality. At 2-3 cups per day, the link rose to 17%. Consumption beyond three cups per day was not associated with additional reductions, and the link between coffee and a lower risk of death by cardiovascular disease weakened when coffee consumption was more than three cups per day. No significant associations were seen between coffee consumption and cancer mortality. 

“Few studies have examined how coffee additives could impact the link between coffee consumption and mortality risk, and our study is among the first to quantify how much sweetener and saturated fat are being added,” said first author Bingjie Zhou, a recent Ph.D. graduate from the nutrition epidemiology and data science program at the Friedman School. “Our results align with the Dietary Guidelines for Americans which recommend limiting added sugar and saturated fat.” 

Limitations of the study include the fact that self-reported recall data is subject to measurement error due to day-to-day variations in food intake. The lack of significant associations between decaffeinated coffee and all-cause mortality could be due to the low consumption among the population studied. 

Source: Tufts University

Categories : Cancer Diet and NutritionTags :

Can Vitamin D Help Prevent Colorectal Cancer?

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The science is promising – but not straightforward

Photo by Michele Blackwell on Unsplash

Justin Stebbing, Anglia Ruskin University

The potential role of vitamin D in preventing and treating colorectal cancer (CRC) has attracted growing research interest – especially as CRC rates are rising, particularly among younger adults. This isn’t a new area of study. Low vitamin D levels have long been linked to a higher risk of developing colorectal cancer.

One large study involving over 12 000 participants found that people with low blood levels of vitamin D had a 31% greater risk of developing CRC compared to those with higher levels. Similarly, another study reported a 25% lower CRC risk among individuals with high dietary vitamin D intake.

Data from the Nurses’ Health Study – a long-term investigation of American nurses – showed that women with the highest vitamin D intake had a 58% lower risk of developing colorectal cancer compared to those with the lowest intake.

Now, a review highlights vitamin D’s promise in colorectal cancer prevention and treatment – but also underscores the complexity and contradictions in current research.

While observational data, which follow people’s use of vitamin D, and mechanistic studies, to investigate how vitamin D works in the laboratory, suggest protective effects, this isn’t confirmed by larger trials.

In fact, randomised controlled trials (RCTs), in which some people receive vitamin D and others don’t, the gold standard by which treatments are judged, reveal inconsistent outcomes. This highlights the need for a balanced approach to its integration into public health strategies.

Vitamin D is synthesised in the skin in response to sunlight and exerts its biological effects through vitamin D receptors (VDRs) found throughout the body, including in colon tissue. When activated, these receptors help regulate gene activity related to inflammation, immune response and cell growth – processes central to cancer development and progression.

Preclinical studies have shown that the active form of vitamin D (calcitriol) can suppress inflammation, boost immune surveillance (the immune system’s ability to detect abnormal cells), inhibit tumour blood vessel growth and regulate cell division – a key factor in cancer development, as demonstrated in my recent research.

Epidemiological studies, which track health outcomes across large populations over time, consistently find that people with higher blood levels of vitamin D have a lower risk of developing CRC. This paints a hopeful picture, suggesting that something as simple as getting more vitamin D – via sun exposure, diet, or supplements – could lower cancer risk.

But the story gets more complicated.

Mixed results

When it comes to medical decision-making, randomised controlled trials (RCTs) are the gold standard. These studies randomly assign participants to receive either a treatment (like vitamin D) or a placebo, helping eliminate bias and isolate cause-and-effect relationships.

Unfortunately, RCTs on vitamin D and CRC have produced mixed results.

For example, the VITAL trial – a major RCT involving over 25 000 participants – found no significant reduction in overall colorectal cancer incidence with 2000 IU/day of vitamin D supplementation over several years.

However, a meta-analysis of seven RCTs did show a 30% improvement in CRC survival rates with vitamin D supplements, suggesting potential benefits later in the disease course rather than for prevention.

On the other hand, the Vitamin D/Calcium Polyp Prevention Trial found no reduction in the recurrence of adenomas (pre-cancerous growths) with supplementation, raising questions about who benefits most, and at what dosage.

Adding to the uncertainty is the question of causation. Does low vitamin D contribute to cancer development? Or does the onset of cancer reduce vitamin D levels in the body? It’s also possible that the observed benefits are partly due to increased sunlight exposure, which itself may have independent protective effects.

The big picture

These discrepancies highlight the importance of considering the “totality of evidence” – treating each study as one piece of a larger puzzle.

The biologic plausibility is there. Observational and mechanistic studies suggest a meaningful link between vitamin D and lower CRC risk. But the clinical evidence isn’t yet strong enough to recommend vitamin D as a standalone prevention or treatment strategy.

That said, maintaining sufficient vitamin D levels – at least 30ng/mL – is a low-risk, cost-effective health measure. And when combined with other strategies like regular screening, a healthy diet, physical activity, and personalised care, vitamin D could still play a valuable role in overall cancer prevention.

Vitamin D is not a miracle cure – but it is part of a much broader picture. Its role in colorectal cancer is promising but still being defined. While it’s not time to rely on supplements alone, ensuring adequate vitamin D levels – through sun exposure, diet, or supplements – remains a smart choice for your health.

Colorectal cancer is a complex disease, and tackling it requires an equally nuanced approach. For now, that means focusing on evidence-based lifestyle changes, regular screenings, and staying informed as new research unfolds.

Justin Stebbing, Professor of Biomedical Sciences, Anglia Ruskin University

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

Categories : Diet and Nutrition Metabolic DisordersTags :

‘Healthy’ Fatty Acid Not as Innocent as it Seems

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Eating a high-fat diet containing a large amount of oleic acid – a type of fatty acid commonly found in olive oil – could drive obesity more than other types of dietary fats, according to a study published in the journal Cell Reports.

The study found that oleic acid, a monounsaturated fat associated with obesity but also tentatively linked to cardiovascular benefits and often touted as a ‘healthy’ fatty acid, causes the body to make more lipid cells. By boosting a signalling protein called AKT2 and reducing the activity of a regulating protein called LXR, high levels of oleic acid resulted in faster growth of the precursor cells that form new lipid cells.

“We know that the types of fat that people eat have changed during the obesity epidemic. We wanted to know whether simply overeating a diet rich in fat causes obesity, or whether the composition of these fatty acids that make up the oils in the diet is important. Do specific fat molecules trigger responses in the cells?” said Michael Rudolph, PhD, assistant professor of biochemistry and physiology at the University of Oklahoma College of Medicine.

Rudolph and his team fed mice a variety of specialised diets enriched in specific individual fatty acids, including those found in coconut oil, peanut oil, milk, lard and soybean oil. Oleic acid was the only one that caused the precursor cells that give rise to fat cells to proliferate more than other fatty acids.

“You can think of the fat cells as an army,” Rudolph said. “When you give oleic acid, it initially increases the number of ‘fat cell soldiers’ in the army, which creates a larger capacity to store excess dietary nutrients. Over time, if the excess nutrients overtake the number of fat cells, obesity can occur, which can then lead to cardiovascular disease or diabetes if not controlled.”

Unfortunately, it’s not quite so easy to isolate different fatty acids in a human diet. People generally consume a complex mixture if they have cream in their coffee, a salad for lunch and meat and pasta for dinner. However, Rudolph said, there are increasing levels of oleic acid in the food supply, particularly when access to food variety is limited and fast food is an affordable option.

“I think the take-home message is moderation and to consume fats from a variety of different sources,” he said. “Relatively balanced levels of oleic acid seem to be beneficial, but higher and prolonged levels may be detrimental. If someone is at risk for heart disease, high levels of oleic acid may not be a good idea.”

Source: University of Oklahoma

Categories : Ageing Diet and NutritionTags :

Consuming a Variety of Flavonoids Extends Life, New Study Suggests

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New research has found that those who consume a diverse range of foods rich in flavonoids, such as tea, berries, dark chocolate, and apples, could lower their risk of developing serious health conditions and have the potential to live longer.

The study was led by a team of researchers from Queen’s University Belfast, Edith Cowan University Perth (ECU), and the Medical University of Vienna and Universitat Wien.

The findings reveal that increasing the diversity of flavonoids within your diet could help prevent the development of health conditions such as type 2 diabetes, cardiovascular disease (CVD), cancer and neurological disease.

Flavonoids are found in plant foods like tea, blueberries, strawberries, oranges, apples, grapes, and even red wine and dark chocolate.

The study in Nature Food followed over 120 000 participants aged 40–70 for over a decade. It is the first study of its kind to suggest that there is a benefit to consuming a wide range of flavonoids beyond that of simply consuming a high quantity.

ECU Research Fellow, first author and co-lead of the study Dr Benjamin Parmenter, made the initial discovery that a flavonoid-diverse diet is good for health.

“Flavonoid intakes of around 500mg a day was associated with a 16% lower risk of all-cause mortality, as well as a ~10% lower risk of CVD, type 2 diabetes, and respiratory disease. That’s roughly the amount of flavonoids that you would consume in two cups of tea.”

Dr Parmenter added, however, that those who consumed the widest diversity of flavonoids, had an even lower risk of these diseases, even when consuming the same total amount. For example, instead of just drinking tea, it’s better to eat a range of flavonoid-rich foods to make up your intake, because different flavonoids come from different foods.

“We have known for some time that higher intakes of dietary flavonoids, powerful bioactives naturally present in many foods and drinks, can reduce the risk of developing heart disease, type 2 diabetes, and neurological conditions like Parkinson’s,” study co-lead Professor Aedín Cassidy from the Co-Centre for Sustainable Food Systems and Institute for Global Food Security at Queen’s said.

“We also know from lab data and clinical studies that different flavonoids work in different ways, some improve blood pressure, others help with cholesterol levels and decrease inflammation. This study is significant as the results indicate that consuming a higher quantity and wider diversity has the potential to lead to a greater reduction in ill health than just a single source.”

Professor Tilman Kuhn from the Medical University of Vienna, Universitat Wien and Queen’s University Belfast was also a co-lead author, noted that the importance of diversity of flavonoid intake has never been investigated until now, making this study very significant as the findings align with popular claims that eating colourful foods are invaluable to maintain good health.

“Eating fruits and vegetables in a variety of colours, including those rich in flavonoids, means you’re more likely to get the vitamins and nutrients you need to sustain a healthier lifestyle,” he said.

The first-ever dietary guidelines for flavonoids were released recently recommending increasing the consumption of flavonoids to maintain health.

“Our study provides inaugural evidence that we may also need to advise increasing diversity of intake of these compounds for optimal benefits,” Dr Parmenter said.

“The results provide a clear public health message, suggesting that simple and achievable dietary swaps, such as drinking more tea and eating more berries and apples for example, can help increase the variety and intake of flavonoid-rich foods, and potentially improve health in the long-term,” Professor Cassidy added.

Source: Edith Cowan University

Categories : Diet and Nutrition NeurologyTags :

What Does Caffeine Do to the Sleeping Brain?

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Caffeine is one of the most widely consumed psychoactive substances in the world, present in tea, coffee, chocolate and energy drinks. In a study published in Nature Communications Biology, a team of researchers from Université de Montréal shed new light on how caffeine can modify sleep and influence the brain’s recovery, both physical and cognitive, overnight.

The research was led by Philipp Thölke, a research trainee at UdeM’s Cognitive and Computational Neuroscience Laboratory (CoCo Lab), and co-led by the lab’s director Karim Jerbi, a psychology professor and researcher at Mila – Quebec AI Institute.

Working with sleep-and-aging psychology professor Julie Carrier and her team at UdeM’s Centre for Advanced Research in Sleep Medicine, the scientists used AI and electroencephalography (EEG) to study caffeine’s effect on sleep.

They showed for the first time that caffeine increases the complexity of brain signals and enhances brain “criticality” during sleep.  Interestingly, this was more pronounced in younger adults.

“Criticality describes a state of the brain that is balanced between order and chaos,” said Jerbi.

“It’s like an orchestra: too quiet and nothing happens, too chaotic and there’s cacophony. Criticality is the happy medium where brain activity is both organised and flexible. In this state, the brain functions optimally: it can process information efficiently, adapt quickly, learn and make decisions with agility.”

Added Carrier: “Caffeine stimulates the brain and pushes it into a state of criticality, where it is more awake, alert and reactive. While this is useful during the day for concentration, this state could interfere with rest at night: the brain would neither relax nor recover properly.”

Nocturnal brain activity

To study how caffeine affects the sleeping brain, Carrier’s team recorded the nocturnal brain activity of 40 healthy adults using an electroencephalogram.  They compared each participant’s brain activity on two separate nights, one when they consumed caffeine capsules three hours and then one hour before bedtime, and another when they took a placebo at the same times.

“We used advanced statistical analysis and artificial intelligence to identify subtle changes in neuronal activity,” said Thölke, the study’s first author. “The results showed that caffeine increased the complexity of brain signals, reflecting more dynamic and less predictable neuronal activity, especially during the non-rapid eye movement (NREM) phase of sleep that’s crucial for memory consolidation and cognitive recovery.”

The researchers also discovered striking changes in the brain’s electrical rhythms during sleep: caffeine attenuated slower oscillations such as theta and alpha waves (generally associated with deep, restorative sleep) and stimulated beta wave activity, which is more common during wakefulness and mental engagement.

“These changes suggest that even during sleep, the brain remains in a more activated, less restorative state under the influence of caffeine,” says Jerbi, who also holds the Canada Research Chair in Computational Neuroscience and Cognitive Neuroimaging. “This change in the brain’s rhythmic activity may help explain why caffeine affects the efficiency with which the brain recovers during the night, with potential consequences for memory processing.”

People in their 20s more affected

The study also showed that the effects of caffeine on brain dynamics were significantly more pronounced in young adults between ages 20 and 27 compared to middle-aged participants aged 41 to 58, especially during REM sleep, the phase associated with dreaming.

Young adults showed a greater response to caffeine, likely due to a higher density of adenosine receptors in their brains. Adenosine is a molecule that gradually accumulates in the brain throughout the day, causing a feeling of fatigue.

“Adenosine receptors naturally decrease with age, reducing caffeine’s ability to block them and improve brain complexity, which may partly explain the reduced effect of caffeine observed in middle-aged participants,” Carrier said.

And these age-related differences suggest that younger brains may be more susceptible to the stimulant effects of caffeine. Given caffeine’s widespread use, the researchers stress the importance of understanding its complex effects on brain activity across different age groups and health conditions.

They add that further research is needed to clarify how these neural changes affect cognitive health and daily functioning, and to potentially guide personalised recommendations for caffeine intake.

Source: University of Montreal

Categories : Diet and Nutrition GastrointestinalTags :

Pilot IBS Study Suggests Mediterranean Diet May be an Alternative to Low FODMAP

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A pilot study from Michigan Medicine researchers found that the Mediterranean diet may provide symptom relief for people with irritable bowel syndrome. For the study, which was published in Neurogastroenterology & Motility, participants were randomised into two groups, one following the Mediterranean diet and the other following the low FODMAP diet, a common restrictive diet for IBS.

In the Mediterranean diet group, 73% of the patients met the primary endpoint for symptom improvement, versus 81.8% in the low FODMAP group.

Irritable bowel syndrome affects an estimated 4-11% of all people, and a majority of patients prefer dietary interventions to medication. The low FODMAP diet leads to symptom improvement in more than half of patients, but is restrictive and hard to follow.

Previous investigations from Michigan Medicine researchers into more accessible alternative diets led to a proposed “FODMAP simple,” which attempted to only restrict the food groups in the FODMAP acronym that are most likely to cause symptoms.

“Restrictive diets, such as low FODMAP, can be difficult for patients to adopt,” said Prashant Singh, MBBS, Michigan Medicine gastroenterologist and lead author on the paper.

“In addition to the issue of being costly and time-consuming, there are concerns about nutrient deficiencies and disordered eating when trying a low FODMAP diet. The Mediterranean diet interested us as an alternative that is not an elimination diet and overcomes several of these limitations related to a low FODMAP diet.”

The Mediterranean diet is already popular among physicians for its benefits to cardiovascular, cognitive, and general health. Previous research on the effect of the Mediterranean diet on IBS, however, had yielded conflicting results.

In this pilot study, two groups of patients, diagnosed with either IBS-D (diarrhoea) or IBS-M (mixed symptoms of constipation or diarrhoea), were provided with either a Mediterranean diet or the restriction phase of a low FODMAP diet for four weeks.

The primary endpoint was an FDA-standard 30% reduction in abdominal pain intensity after four weeks.

This study was the first randomised controlled trial to compare the Mediterranean diet to another potential diet. While the Mediterranean diet did provide symptom relief, the low FODMAP group experienced a greater improvement measured by both abdominal pain intensity and IBS symptom severity score.

Researchers found the results of this pilot study, which 20 patients completed, sufficiently encouraging to warrant future, larger controlled trials to investigate the potential of the Mediterranean diet as an effective intervention for patients with IBS.

“This study adds to a growing body of evidence which suggests that a Mediterranean diet might be a useful addition to the menu of evidence-based dietary interventions for patients with IBS,” said William Chey, MD, chief of Gastroenterology at the University of Michigan, president-elect of the American College of Gastroenterology, and senior author on the paper.

The researchers believe studies comparing long-term efficacy of the Mediterranean diet with long-term outcomes following the reintroduction and personalisation phases of low FODMAP are needed.

Source: Michigan Medicine – University of Michigan

Categories : Ageing Diet and NutritionTags :

Quality of Carbohydrates Matters for Healthy Ageing

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Intakes of dietary fibre as well as high-quality and total carbohydrates in midlife were favourably linked to healthy aging and other positive health outcomes in older women, according to a new study appearing in the journal JAMA Network Open.

“We’ve all heard that different carbohydrates can affect health differently, whether for weight, energy, or blood sugar levels. But rather than just look at the immediate effects of these macronutrients, we wanted to understand what they might mean for good health 30 years later,” said Andres Ardisson Korat, a scientist at Tufts University and lead author of the study. “Our findings suggest that carbohydrate quality may be an important factor in healthy aging.”

Researchers from Tufts University and Harvard T.H. Chan School of Public Health analysed data from Nurses’ Health Study questionnaires collected every four years between 1984 and 2016. They examined the midlife diets and eventual health outcomes of more than 47 000 women who were between the ages of 70 and 93 in 2016.  Intakes of total carbohydrates, refined carbohydrates, high-quality (unrefined) carbohydrates, carbohydrates from whole grains, fruits, vegetables, and legumes, dietary fibre, and the dietary glycaemic index and glycaemic load were derived from the validated food-frequency questionnaires. The researchers defined healthy aging as the absence of 11 major chronic diseases, lack of cognitive and physical function impairments, and having good mental health, as self-reported in the Nurses’ Health Study questionnaires. In the new study, 3706 participants met the healthy aging definition.

The analysis showed intakes of total carbohydrates, high-quality carbohydrates from whole grains, fruits, vegetables, and legumes, and total dietary fibre in midlife were linked to 6 to 37% greater likelihood of healthy aging and several areas of positive mental and physical health. In the other direction, intakes of refined carbohydrates (carbohydrates from added sugars, refined grains, and potatoes) and starchy vegetables were associated with 13% lower odds of healthy aging.

“Our results are consistent with other evidence linking consumption of fruits and vegetables, whole grains, and legumes with lower risks of chronic diseases, and now we see the association with physical and cognitive function outcomes,” said senior author Qi Sun, associate professor in the departments of nutrition and epidemiology at Harvard Chan School.

The authors note as a limitation that the study population was composed mostly of white health professionals; future research will be necessary to replicate these findings in more diverse cohorts. 

Ardisson Korat also noted that additional work is needed to understand the potential mechanisms linking dietary fiber and high-quality carbohydrates to healthy aging.

“Studies are starting to find an association between food choices in midlife and quality of life in later years. The more we can understand about healthy aging, the more science can help people live healthier for longer,” added Ardisson Korat.

Source: Tufts University

Categories : Diet and NutritionTags :

Adding Chili to a Meal Helps Prevent Overconsumption

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Throwing a little heat on your meal might be an effective strategy for cutting back on calories, according to a new study led by researchers at Penn State.

Scientists at the University’s Sensory Evaluation Center examined how increasing “oral burn” – the spicy taste from ingredients like chili pepper – affects how much food people consume during a meal. The findings, available online now and slated to publish in the October issue of the journal Food Quality and Preference, suggest that making the meal slightly spicier led participants to eat less, consuming fewer calories.

“We know from previous studies that when people slow down, they eat significantly less,” said Paige Cunningham, a postdoctoral researcher and lead author on the study who earned her doctorate in nutritional sciences from Penn State in 2023. “We suspected that making a meal spicier might slow people down. We thought, let’s test, under controlled experimental conditions in the lab, if adding a small amount of spice, but not so much that the meal is inedible, will make people eat slower and therefore eat less.”

The researchers found that increasing spiciness slightly using dried chili pepper slowed down eating and reduced the amount of food and energy consumed at a meal, all without negatively affecting the palatability of the dish.

“This points to added chilies as a potential strategy for reducing the risk of energy overconsumption,” said John Hayes, Penn State professor of food science and corresponding author on the paper. “While portion control wasn’t the explicit goal of this study, our results suggest this might work. Next time you’re looking to eat a little less, try adding a blast of chilies, as it may slow you down and help you eat less.”

Source: Penn State

Categories : Diet and Nutrition OphthalmologyTags :

Vitamin Supplements Slow Down the Progression of Glaucoma

On By Peter Van Dyk
Photo by Ksenia Chernaya

A vitamin supplement that improves metabolism in the eye appears to slow down damage to the optic nerve in glaucoma. Promising results have been published in the journal Cell Reports Medicine. The researchers behind the study have now started a clinical trial on patients.

In glaucoma, the optic nerve is gradually damaged, leading to vision loss and, in the worst cases, blindness. High pressure in the eye drives the disease, and eye drops, laser treatment or surgery are therefore used – with varying effect – to lower the pressure in the eye and thus slow down the disease.

Glaucoma researchers have long theorised that the substance homocysteine is somehow relevant to understanding the disease. Now, researchers at Karolinska Institutet have investigated the role of homocysteine in several ways. In the current study, the researchers discovered that when rats with glaucoma were given elevated levels of homocysteine, their disease did not worsen. 

Investigated metabolic pathways

The researchers also found that high levels of homocysteine in the blood of people with glaucoma did not correlate with how quickly the disease progressed, and that glaucoma was not more common in people with a genetic susceptibility to forming high levels of homocysteine. Based on these findings, the researchers concluded that homocysteine does not drive the disease but is a consequence of it.

Since homocysteine is a natural part of the body’s metabolism, the researchers wanted to investigate metabolic pathways involving homocysteine in both rodents and humans with glaucoma. They then saw several abnormalities, the most important of which were metabolic changes linked to the retina’s ability to use certain vitamins. This change meant that metabolism was slowed down locally in the retina – and this played a role in the development of the disease. 

“Our conclusion is that homocysteine is a bystander in the disease process, not a player. Altered homocysteine levels may reveal that the retina has lost its ability to use certain vitamins that are necessary to maintain healthy metabolism. That’s why we wanted to investigate whether supplements of these vitamins could protect the retina”, says co-lead on the paper James Tribble, researcher and assistant professor at the Department of Clinical Neuroscience at Karolinska Institutet.

Promising results lead to clinical trial

In experiments on mice and rats with glaucoma, the researchers gave supplements of the B vitamins B6, B9 and B12, as well as choline. This had a positive effect. In mice that had a slower developing glaucoma, the damage to the optic nerve was completely halted. In rats, which had a more aggressive form of the disease with faster progression, the disease was slowed down. 

In these experiments, eye pressure was left untreated, which the researchers highlight as particularly interesting – it suggests that the vitamin mix affects the disease in a different way than lowering eye pressure does. 

“The results are so promising that we have started a clinical trial, with patients already being recruited at S:t Eriks Eye Hospital in Stockholm”, says James Tribble. 

Both patients with primary open-angle glaucoma (slower progression) and pseudoexfoliation glaucoma (faster progression) are included. 

Read more about the clinical trial here. 

Source: Karolinska Institutet

Categories : Diet and NutritionTags :

Intermittent Fasting: Is it the Calories or Carbs that Count?

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Adam Collins, University of Surrey

Intermittent fasting is not only a useful tool for weight loss, it’s also shown to have many benefits for metabolic health – independent of weight loss. Yet many people may find intermittent fasting to be a challenge, especially if following the 5:2 version of the diet where calories are severely restricted two days a week.

But my latest study shows that you don’t need to severely restrict your calories to get the metabolic benefits of intermittent fasting. Even just restricting the number of carbs you eat twice a week may be enough to improve your metabolic health.

Intermittent fasting appears to be so beneficial for health because of the way it alters our metabolism.

After a meal, our body enters the postprandial state. While in this state, our metabolism pushes our cells to use carbohydrates for immediate energy, while storing some of these carbs as well as fat for later use. But after several hours without food, in the postabsorptive “fasted” state, our metabolism switches to using some of our fat stores for energy.

In this regard, intermittent fasting ensures a better balance between the sources it uses for energy. This leads to improved metabolic flexibility, which is linked with better cardiometabolic health. In other words, this means lower risk of cardiovascular disease, insulin resistance and type 2 diabetes.

My colleagues and I previously ran a study to demonstrate the effects of a fast on the body. We observed that following a day of both total fasting or severe calorie restriction (eating around only 25% of each person’s daily calorie requirements), the body was better at clearing and burning the fat of a full English breakfast the next day. Fasting shifted the body from using carbs to using fat. This effect carried on both during the fast and the next day.

Our research has also compared the effects of intermittent fasting to a calorie-matched or calorie-restricted diet. Both groups followed the diet until they lost 5% of their body weight.

Despite both groups losing the same 5% of body weight, and at the same rate, the intermittent fasting group had greater improvements in their metabolic handling, similar to what we saw in the previous trial.

Other researchers who have compared the effects of the 5:2 variant of the intermittent fasting diet to a calorie-matched, calorie-restricted diet have also found fasting is beneficial for metabolic health.

Metabolic health benefits

But why exactly is intermittent fasting so beneficial for metabolic health? This is a question I sought to answer in my latest study.

For people who follow the 5:2 intermittent fasting diet, typical fasting days are, by their nature, very low in calories – equating to only a few hundred calories per day. Because people are consuming so few calories on fasting days, it also means they’re consuming very few carbohydrates. Given the postprandial state is governed by carbohydrate availability, this begged the question as to whether it’s the calorie restriction or the carbohydrate restriction that’s creating the metabolic effect when intermittent fasting.

We recruited 12 overweight and obese participants. Participants were first given a very low-carb diet one day. Another day, they were given a severely calorie-restricted diet (around 75% fewer calories than they’d normally eat). After each fasting day, we gave them a high-fat, high-sugar meal (similar to an English breakfast) to see how easily their bodies burned fat.

What we found was that the shift to fat burning and improved fat handling of the high-calorie meal were near identical following both the traditional calorie-restricted “fast” day and the low-carb day. In other words, restricting carbs can elicit the same favourable metabolic effects as fasting.

It will be important now for more studies to be conducted using a larger cohort of participants to confirm these findings.

Such findings may help us address some of the practical problems we face with intermittent fasting and traditional low-carb diets.

For intermittent fasting diets, severe calorie restriction on fasting days can increase the risk of nutritional deficiencies if not careful. It can similarly be a trigger for disordered eating.

Strict carb restriction can also be challenging to adhere to long-term, and may lead to an unhealthy fear of carbs.

The other limitation of both intermittent fasting and continuous carb restriction is that weight loss is a likely outcome. Hence these approaches are not universally beneficial for those who need to improve their health without losing weight or those looking to maintain their weight.

We are now testing the feasibility of an intermittent carb restriction diet, or a low-carb 5:2. So instead of restricting calories two days a week, you would restrict the number of carbs you consume twice a week. If this is proven to be beneficial, it would offer the benefits of fasting without restricting calories on “fast” days.

Adam Collins, Associate Professor of Nutrition, University of Surrey

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