Diet

Posted on Diet

Calorie restriction study reveals complexities in how diet impacts aging

Penn State researchers may have uncovered another layer of complexity in the mystery of how diet impacts ageing. A new study led by researchers in the Penn State College of Health and Human Development examined how caloric restriction affected a person’s telomeres—sections of genetic bases that function like protective caps at the ends of chromosomes.

The team published their results in Aging Cell. Analyzing data from a two-year study of caloric restriction in humans, the researchers found that people who restricted their calories lost telomeres at different rates than the control group—even though both groups ended the study with telomeres of roughly the same length. Previous research has shown that restricting calories by 20% to 60% has been shown to promote longer life in many animals.

Over the course of human life, every time a person’s cells replicate, some telomeres are lost when chromosomes are copied to the new cell. When this happens, the overall length of the cell’s telomeres becomes shorter. After cells replicate enough times, the protective cap of telomeres completely dissipates. Then, the genetic information in the chromosome can become damaged, preventing the cell’s future reproduction or proper function. A cell with longer telomeres is functionally younger than a cell with short telomeres, meaning that two people with the same chronological age could have different biological ages depending on the length of their telomeres. 

Typical aging, stress, illness, genetics, diet and more can all influence how often cells replicate and how much length the telomeres retain, according to Idan Shalev, associate professor of biobehavioral health at Penn State. Shalev led the researchers who analyzed genetic samples from the national CALERIE study — the first randomized clinical trial of human calorie restriction. Shalev and his team sought to understand the effect of caloric restriction on telomere length in people. Because telomere length reflects how quickly or slowly a person’s cells are aging, examining telomere length could allow scientists to identify one way in which caloric restriction may slow aging in humans.

“There are many reasons why caloric restriction may extend human lifespans, and the topic is still being studied,” said Waylon Hastings, who earned his doctorate in biobehavioral health at Penn State in 2020 and was lead author of this study. “One primary mechanism through which life is extended relates to metabolism in a cell. When energy is consumed within a cell, waste products from that process cause oxidative stress that can damage DNA and otherwise break down the cell. When a person’s cells consume less energy due to caloric restriction, however, there are fewer waste products, and the cell does not break down as quickly.” 

The researchers tested the telomere length of 175 research participants using data from the start of the CALERIE study, one year into the study and the end of the study after 24 months of caloric restriction. Approximately two-thirds of study participants participated in caloric restriction, while one-third served as a control group.

During the study, results showed that telomere loss changed trajectories. Over the first year, participants who were restricting caloric intake lost weight, and they lost telomeres more rapidly than the control group. After a year, the weight of participants on caloric restriction was stabilized, and caloric restriction continued for another year. During the second year of the study, participants on caloric restriction lost telomeres more slowly than the control group. At the end of two years, the two groups had converged, and the telomere lengths of the two groups was not statistically different.

“This research shows the complexity of how caloric restriction affects telomere loss,” Shalev said. “We hypothesized that telomere loss would be slower among people on caloric restriction. Instead, we found that people on caloric restriction lost telomeres more rapidly at first and then more slowly after their weight stabilized.”

Shalev said the results raised a lot of important questions. For example, what would have happened to telomere length if data had been collected for another year? Study participants are scheduled for data collection at a 10-year follow-up, and Shalev said that he was eager to analyze those data when they become available.

Posted on Diet

Swapping red meat for herring/sardines could save up to 750,000 lives/year in 2050

Adopting forage fish diet would be especially helpful in the Global South, say researchers
Adopting a forage fish diet would be especially helpful in the Global South, say researchers

Swapping red meat for ‘forage fish’, such as herring, sardines, and anchovies, could save up to 750,000 lives a year in 2050 and significantly reduce the prevalence of disability due to diet-related disease, suggests a data analysis published in the open-access journal BMJ Global Health. 

Adopting this type of diet would be especially helpful for low—and middle-income countries, where these fish are cheap and plentiful and where the toll taken by heart disease, in particular, is high, say the researchers.

Mounting evidence links red and processed meat consumption with heightened risks of non-communicable disease, which accounted for around 70% of all deaths globally in 2019, explain the researchers.

Of these, coronary heart disease, stroke, diabetes, and bowel cancer made up nearly half (44%) of this toll, with coronary artery disease taking the lion’s share.

Marine forage fish, which are predated by larger fish, are rich in omega-3 long-chain polyunsaturated fatty acids (DHA and EPA), the intake of which may prevent coronary heart disease, as well as being abundant in calcium and vitamin B12. The researchers note that they also have the lowest carbon footprint of any animal food source.

But currently, three-quarters of the forage fish catch, including a significant amount caught off the coasts of countries enduring food insecurity and malnutrition in the Global South, is ground into fishmeal and fish oil—products that are mostly used for fish farming, destined for high-income consumers, the researchers add.

While several studies have revealed the potential nutritional and environmental benefits of forage fish, it’s unclear to what extent they might cut the global burden of disease if substituted for red meat. 

To address this knowledge gap, the researchers created four different scenarios, each representing a different pattern of forage fish allocation globally. They used data on projected red meat consumption in 2050 for 137 countries and historical data on the forage fish catch from marine habitats.

The 4 scenarios comprised: domestic supply prioritised, with forage fish caught for national consumption or red meat substitution (I); minimised meat intake, with substitution prioritised in countries with meat consumption from sheep and cattle above the recommended level of 15 kcal (II); adequate fish intake, prioritising countries with fish consumption below the recommended level of 40 kcal (III); and equal percentage of red meat replaced in all countries (IV), determined by the availability of forage fish.

Their analysis shows that if widely adopted for direct human consumption, forage fish would potentially provide substantial public health benefits, particularly in terms of reducing the occurrence of coronary heart disease.

Globally, this approach could prevent half a million to 750,000 deaths from diet-related disease in 2050—and deaths from coronary heart disease in particular—and it could avert 8–15 million years of life lived with a disability, most of which are concentrated in low and middle-income countries. 

The limited supply of forage fish isn’t sufficient to replace all red meat, acknowledge the researchers. However, it could potentially increase the daily per capita consumption of fish to close to the recommended level of 40 kcal in most countries and reduce deaths from coronary heart disease, stroke, diabetes, and bowel cancer by 2% in 2050.

Of the four scenarios, scenario I averted the fewest deaths. The analysis suggests that allocating all forage fish to regions with the lowest fish intake—mainly in lower and middle-income countries (scenario III)—would more effectively reduce the global disease burden.

The researchers point out that global marketing and trade in forage fish would need to be expanded for landlocked countries without direct access to seafood, such as Mongolia, Turkmenistan, and other African countries.

They acknowledge that “despite the theoretical potential of forage fish, several barriers, such as fish meal and oil processing, overfishing, climate change, and cultural acceptance, may prevent the health benefits of forage fish from being realised.” 

“Multi-sectoral policy coordination and action (e.g., prioritising access to affordable fish, such as forage fish, for the poor and promoting the use of nutrient-rich microalgae as fish feed) could help to address some of these barriers,” they suggest.

They say culturally tailored interventions that promote healthy lifestyles, increase family and community support, and raise awareness of the relationship between disease and diet could all enhance the chances of successful behaviour and diet change.

They suggest that other strategies, such as climate change-impact menu labels on food items and consumer education on the high nutritional value and lower chemical levels in forage fish, could also help promote the switch away from red meat to forage fish.

Posted on Diet, Mental health

Keto diet improves severe mental illness says new research

A small clinical trial led by Stanford Medicine found that the metabolic effects of a ketogenic diet may help stabilize the brain.
A small clinical trial led by Stanford Medicine found that a ketogenic diet’s metabolic effects may help stabilize the brain.

For people living with serious mental illness like schizophrenia or bipolar disorder, standard treatment with antipsychotic medications can be a double-edged sword. While these drugs help regulate brain chemistry, they often cause metabolic side effects such as insulin resistance and obesity, which are distressing enough that many patients stop taking the medications.

Now, a pilot study led by Stanford Medicine researchers has found that a ketogenic diet not only restores metabolic health in these patients as they continue their medications, but it further improves their psychiatric conditions. The results,suggest that a dietary intervention can be a powerful aid in treating mental illness.

“It’s very promising and very encouraging that you can take back control of your illness in some way, aside from the usual standard of care,” said Shebani Sethi, MD, associate professor of psychiatry and behavioral sciences and the first author of the new paper.

The senior author of the paper is Laura Saslow, PhD, associate professor of health behavior and biological sciences at the University of Michigan.

Making the connection

Sethi, who is board certified in obesity and psychiatry, remembers when she first noticed the connection. As a medical student working in an obesity clinic, she saw a patient with treatment-resistant schizophrenia whose auditory hallucinations quieted on a ketogenic diet.

That prompted her to dig into the medical literature. There were only a few, decades-old case reports on using the ketogenic diet to treat schizophrenia, but there was a long track record of success in using ketogenic diets to treat epileptic seizures.

“The ketogenic diet has been proven to be effective for treatment-resistant epileptic seizures by reducing the excitability of neurons in the brain,” Sethi said. “We thought it would be worth exploring this treatment in psychiatric conditions.”

A few years later, Sethi coined the term metabolic psychiatry, a new field that approaches mental health from an energy conversion perspective.

Meat and vegetables

In the four-month pilot trial, Sethi’s team followed 21 adult participants who were diagnosed with schizophrenia or bipolar disorder, taking antipsychotic medications, and had a metabolic abnormality — such as weight gain, insulin resistance, hypertriglyceridemia, dyslipidemia or impaired glucose tolerance. The participants were instructed to follow a ketogenic diet, with approximately 10% of the calories from carbohydrates, 30% from protein and 60% from fat. They were not told to count calories.

“The focus of eating is on whole non-processed foods including protein and non-starchy vegetables, and not restricting fats,” said Sethi, who shared keto-friendly meal ideas with the participants. They were also given keto cookbooks and access to a health coach. 

The research team tracked how well the participants followed the diet through weekly measures of blood ketone levels. (Ketones are acids produced when the body breaks down fat — instead of glucose — for energy.) By the end of the trial, 14 patients had been fully adherent, six were semi-adherent and only one was non-adherent.

Feeling better

The participants underwent a variety of psychiatric and metabolic assessments throughout the trial.

Before the trial, 29% of the participants met the criteria for metabolic syndrome, defined as having at least three of five conditions: abdominal obesity, elevated triglycerides, low HDL cholesterol, elevated blood pressure and elevated fasting glucose levels. After four months on a ketogenic diet, none of the participants had metabolic syndrome.

On average, the participants lost 10% of their body weight; reduced their waist circumference by 11% percent; and had lower blood pressure, body mass index, triglycerides, blood sugar levels and insulin resistance.

“We’re seeing huge changes,” Sethi said. “Even if you’re on antipsychotic drugs, we can still reverse the obesity, the metabolic syndrome, the insulin resistance. I think that’s very encouraging for patients.”

The psychiatric benefits were also striking. On average, the participants improved 31% on a psychiatrist rating of mental illness known as the clinical global impressions scale, with three-quarters of the group showing clinically meaningful improvement. Overall, the participants also reported better sleep and greater life satisfaction.

“The participants reported improvements in their energy, sleep, mood and quality of life,” Sethi said. “They feel healthier and more hopeful.”

The researchers were impressed that most of the participants stuck with the diet. “We saw more benefit with the adherent group compared with the semi-adherent group, indicating a potential dose-response relationship,” Sethi said.

Alternative fuel for the brain

There is increasing evidence that psychiatric diseases such as schizophrenia and bipolar disorder stem from metabolic deficits in the brain, which affect the excitability of neurons, Sethi said.

The researchers hypothesize that just as a ketogenic diet improves the rest of the body’s metabolism, it also improves the brain’s metabolism.

“Anything that improves metabolic health in general is probably going to improve brain health anyway,” Sethi said. “But the ketogenic diet can provide ketones as an alternative fuel to glucose for a brain with energy dysfunction.”

Likely there are multiple mechanisms at work, she added, and the main purpose of the small pilot trial is to help researchers detect signals that will guide the design of larger, more robust studies.  

As a physician, Sethi cares for many patients with both serious mental illness and obesity or metabolic syndrome, but few studies have focused on this undertreated population.

She is founder and director of the metabolic psychiatry clinic at Stanford Medicine

“Many of my patients suffer from both illnesses, so my desire was to see if metabolic interventions could help them,” she said. “They are seeking more help. They are looking to just feel better.”

Posted on Diet, Multiple Sclerosis

MS Diets (Wahls, Swank, OMS, Best Bet, Healing MS)

A description of 5 popular diets purported to treat multiple sclerosis: Wahls Protocol, Swank Diet, Overcoming Multiple Sclerosis (OMS), Best Bet Diet, Healing multiple sclerosis