Even in later life, eating well pays off; researchers reveal that healthier diets can dramatically extend the lifespan of frail adults and cut their risk of early death.
Study: Combined Effects of Diet Quality Scores and Frailty on All-Cause Mortality and Life Expectancy in Middle-Aged and Older Adults. Image credit: PeopleImages/Shutterstock.com
Frailty is a known risk factor for premature death in the elderly, but its interrelationship with diet quality is poorly known. A recent paper in Nutrients examines the interaction of frailty and nutritional quality in lifespan and mortality after middle life.
Introduction
The world’s population is growing older and living longer. By 2050, the number of people over 60 is expected to double from the 2000 figures, and the population above 80 will increase fourfold. This emphasizes the need to ensure healthy aging. Frailty is a significant risk factor for disability and death. Frail people are more likely to fall, be hospitalized, suffer bone breaks, become disabled, develop multiple acute or chronic illnesses, and die earlier than expected.
The expected lifespan of a population is an accurate and actionable measure of its health. Physical activity and a healthy diet typically increase lifespan, while smoking and drinking reduce it.
Poor diet quality deprives the consumer of many nutrients at adequate levels and prevents the proper utilization of available resources. Many different dietary scores have been devised, but there are so many options with high variability that comparability is difficult. However, their combined use might yield the most useful results in framing dietary recommendations.
Since few researchers have looked at the interaction of frailty and diet quality, the current study addressed this gap, seeking to gather evidence that might help extend the years of healthy life in the aging population.
About the study
The study used UK Biobank data from 151,628 participants, chosen because they had undergone one or more dietary evaluations. Their frailty was assessed using two indices: frailty phenotype (FP) and frailty index (FI).
The FP used criteria like weight loss, exhaustion, weakness, slow walking, and little physical activity. Those with three or more of these were frail, while the pre-frail had one or two criteria.
The FI included the number of present criteria divided by the total, with frailty increasing as the score went higher (≥0.24 or above means frail, while 0.12 to 0.24 meant pre-frail, with <0.12 being robust)
Diet quality was assigned using a variety of eating scores:
- Alternate Healthy Eating Index (AHEI)
- Dietary Approaches to Stop Hypertension (DASH) score
- Mediterranean diet (MED) score
- Dietary Inflammatory Index (DII)
- Three plant-based diet indices
- overall PDI
- healthful PDI
- unhealthful PDI
Diet quality scores were then classified into tertiles, from unhealthy to healthy. Frailty and diet quality were analyzed together after adjusting for deprivation, medical conditions, unhealthy habits, and a family history of cancer or cardiovascular disease.
Study findings
The study period lasted a median of 12.2 years. Over this period, there were 8,231 deaths. The highest death rates were among the increasingly frail individuals. Similarly, those with the worst diets had the highest mortality.
People who were frail and had the poorest diets were much more likely to die than those who were robust and ate healthily. That is, frail individuals with a poor diet quality had about double the risk of death when assessed by the FI and nearly triple the risk when assessed by the FP, compared to non-frail individuals with a healthy diet.
The risk increased steadily from a healthy to an unhealthy diet, but the magnitude was higher among the frail, especially when using the FP criteria. Conversely, at all frailty levels, better diet quality reduced the risk of death and increased expected lifespan in direct proportion to the health-promoting content of the diet.
Using 50 years as the cutoff, life expectancy in frail men (by the FI) with the lowest diet quality was reduced by ~1 to 3 years. The exact degree of reduction varied with the diet score used. For females, the reduction ranged from six months to 2.4 years. When the FP was used, the reductions in life expectancy among frail men and women ranged between 2.1 and 4.5 years, vs 1.6 to 5.1 years, respectively.
These findings are impressive as they embraced a spectrum of dietary assessments, which probably included various nutrients within multiple foods. Moreover, the effects held steady across both sexes and were independent of the effects of drinking, smoking, other medical conditions, medication use, and socioeconomic factors.
The findings were consistent with two different evaluations of frailty, though the FP had stronger associations with diet quality compared to the FI. The FP is based on physical function and directly reflects the effects of poor nutrition and the loss of physical strength. In contrast, using multiple other conditions in the FI tends to partly obscure the effect of frailty and diet.
Biologically, healthy diets are, at their core, the same. They supply an abundance of plant-based foods and adequate antioxidants, dietary fiber, and anti-inflammatory components while limiting free simple sugars and added salt.
Frailty may increase individual vulnerability to poor diet quality in multiple ways. Both are pro-inflammatory. An unhealthy diet is pro-oxidant, worsening oxidative stress and frailty. Impaired metabolism is common in frail people, resulting in high glucose levels and insulin resistance, exacerbated by high-fat diets rich in refined carbohydrates. Again, inadequate food intake by frail people leads to nutrient deficiency. The association of poor nutrition and frailty with weakened immunity and increased infection rate increases the risk of death.
The findings emphasize the universal benefit of a healthy diet even as physical frailty increases and show that the negative effects of frailty can be mitigated, but not necessarily reversed, through healthier dietary habits.
Importantly, the research underscores that it is never too late to adopt healthier dietary habits.”
However, there could be a two-way relationship between diet and frailty, and frail people should be encouraged to switch to a healthy diet. To achieve this, they may require help to overcome functional, logistical, or medical restrictions, which indicates the need for integrated strategies to detect frailty and provide care, as well as nutritional programs.
The authors also noted limitations of the research, including that dietary data came from self-reported 24-hour recalls, which may introduce reporting errors, and that the UK Biobank cohort is not fully representative of the general UK population, which could affect generalizability.
Conclusions
A healthier diet appears to reduce, rather than fully compensate for, the presence of frailty. This highlights the importance of improving diet quality to ensure better quality of life while aging. “Evidence suggests that it is never too late to adopt healthier dietary habits for significant health benefits.”
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