A recent study published in JAMA Network Open has provided new insights into how dietary habits influence epigenetic aging in women.
The research, conducted by scientists at the University of California, San Francisco (UC San Francisco), reveals a significant connection between sugar intake and an increase in biological age, as measured by an epigenetic clock.
Conversely, diets rich in antioxidants and anti-inflammatory foods appear to slow down the aging process. This study offers important findings, particularly in the context of racial diversity, as it includes a cohort of both Black and white female participants.
The Study’s Background and Participant Details
The research draws on data from the National Heart, Lung, and Blood Institute Growth and Healthy Study (NGHS), a long-term study that initially enrolled participants between the ages of 9 and 19 from 1987 to 1997. The primary goal of the NGHS was to investigate heart and metabolic health across different stages of life.
Between 2015 and 2019, the researchers conducted a follow-up study with the same cohort, who were by then aged 36 to 43 years. This follow-up provided an opportunity to explore the relationship between diet and epigenetic aging, using the dietary data collected during this period.
Participants were asked to complete a 3-day food diary, which allowed researchers to calculate the amount of added sugar in their diets. The researchers also evaluated adherence to the Mediterranean diet, the Alternative Healthy Eating Index, and a newly developed nutrient score specifically designed for this study.
This nutrient index, which ranged from 0 to 24, was based on the intake of key micronutrients known for their potential health benefits. The micronutrients included in the index were vitamin A, vitamin E, vitamin C, folate, vitamin B12, zinc, selenium, magnesium, fiber, monounsaturated fatty acids, isoflavones, and sugar.
How Diet Influences Epigenetic Age
To measure biological age, researchers collected saliva samples from 342 participants, half of whom were Black and half white. Biological age was assessed using an algorithm known as GrimAGE2, a machine-learning-based epigenetic clock.
GrimAGE2 estimates biological age by analyzing methylation patterns at specific points on the genome, particularly those related to exposure to c-reactive protein (a marker of inflammation) and hemoglobin A1C (a marker of blood sugar levels).
The study found a striking correlation between sugar intake and accelerated aging. Specifically, the researchers discovered that for each additional gram of sugar consumed daily, the GrimAGE2 score increased by seven days, indicating that higher sugar intake is associated with faster biological aging.
On the other hand, participants who adhered more closely to the Mediterranean diet, the Alternate Healthy Eating Index, or the newly developed nutrient index had lower GrimAGE2 scores, suggesting that these diets may help reduce the rate of biological aging.
The Significant of These Findings
The authors of the study emphasized that their findings align with previous research on diet and aging. However, they also highlighted the uniqueness of their study, noting that it is the first to examine the effect of diet on the epigenetic age of Black women. This is significant, as Black women have historically been underrepresented in health research, yet they face distinct health challenges that can impact aging.
The study suggests that a high-quality diet rich in antioxidants and anti-inflammatory nutrients has a protective effect against biological aging, while high sugar consumption accelerates it. This underscores the importance of dietary choices in managing the aging process and promoting long-term health.
Limitations and Expert Insights
Despite the study’s important contributions, it does have limitations. One key limitation is that GrimAGE2 was originally trained on individuals aged 40 to 92 years, whereas the average age of participants in this study was slightly younger, at 39.2 years. This age difference may influence the accuracy of the GrimAGE2 predictions for this cohort.
Nonetheless, experts in the field have recognized the value of epigenetic clocks like GrimAGE2 in aging research. Lorna Harries, PhD, a professor of molecular genetics at the University of Exeter College of Medicine and Health in the United Kingdom, who was not involved in the study, provided insights into the utility of these tools.
“Presently, they remain one of the very few tools we have which allow us to measure aging at the level of cells and molecules in living people,” she told Medical News Today.
“If we are to develop interventions that interact with cellular aging, we need tools to be able to measure the effect of our interventions in living people. One thing to remember, though, is that different clocks such as GrimAGE or the methylation clocks may be measuring different aspects of cell physiology, not all of which will link directly to functional outcomes.”
The Relationship Between Inflammation, Blood Sugar, and Aging
The GrimAGE2 algorithm is particularly relevant for aging studies because it focuses on two key factors: inflammation and blood sugar levels. Both factors are known to play interconnected roles in the aging process, although this study did not investigate the specific mechanisms involved.
Dr. Harris elaborated on the potential impact of metabolic imbalances on cellular aging.
“Things that mess with your metabolism — [for example,] too much sugar, too much fat — can set up a situation where cells become stressed, and stressed cells can age faster, or acquire traits such as the production of inflammatory factors that contribute to cellular and systemic aging,“ she explained.
High blood sugar levels can also lead to the formation of advanced glycation and products (AGEs), harmful compounds that drive inflammation and accelerate aging at both the cellular and systemic levels.
Dr. Kubanych Takyrbashev, a health and wellness advisor at NOA, who was not involved in the study, echoed these concerns. “In my [own] research, I’ve found that when blood sugar levels are consistently elevated, glucose molecules can bind to proteins in glycation,“ he told Medical News Today.
“This creates harmful compounds called AGEs that accumulate in tissues and accelerate cellular aging,“ he explained.
Dr. Takyrbashev also highlighted the role of oxidative damage in aging, saying, “Based on my clinical experience, high sugar intake increases the production of free radicals, leading to oxidative damage to DNA, proteins, and lipids. This damage accumulates over time and contributes to premature aging of cells and tissues.”
The Role of Obesity and BMI in the Study
While the study adjusted its results for various factors, one notable characteristic of the cohort was the high average body mass index (BMI) of 32.5, which falls within the range of obesity. This is particularly significant because obesity is closely linked with insulin resistance, a known contributor to cellular aging.
Dr. Harries pointed out that although BMI and other confounding factors were controlled for in the analysis, it is not always possible to eliminate all confounding effects.
“Things like BMI are usually controlled for as confounders. However, it is not always possible to adjust away all the confounding, so it’s possible that there may be a residual effect, since BMI is tightly linked with insulin resistance, a known cause of cellular aging,” she said.
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