Category: Nutrition

This one is worth reading carefully, because the headline version of it that circulates online — including in the first draft of this article — misstates what was found.

The study

Researchers analyzed 713 women aged 70 to 79 in the Women’s Health and Aging Studies in Baltimore, and published the results in the Journal of the American Geriatrics Society. Rather than rely on people’s accounts of what they ate, the researchers measured serum carotenoids — the plant pigments that end up in the blood after eating fruit and vegetables, and a far more reliable marker than a food questionnaire. Physical activity was measured separately. Over five years of follow-up, 82 participants died.

What it actually found

• Higher total carotenoids were associated with better survival.
• Women in the highest third of total carotenoids were more likely to survive than those in the lowest third.
• Physical activity was independently associated with better survival.
• The women who were both most physically active and had the highest fruit and vegetable intake were around eight times more likely to survive the five-year follow-up than women lowest in both.

What to take from it

The researchers described both factors as modifiable, and that is the practical point. This is observational research, so it cannot prove that changing your diet at 75 changes your survival. But the two things it points at — eating actual plants and moving your body — are low-risk, cheap, and supported by a great deal of other evidence.

It is also a useful corrective to a common assumption in elder care: that nutrition stops mattering past a certain age. In this cohort it was still measurable in the blood, and still tracked with who was alive five years later.

Sources

• Journal of the American Geriatrics Society — Fruit and vegetable intake, physical activity, and mortality in older community-dwelling women (full text)
• Johns Hopkins Bloomberg School of Public Health — Exercise and a healthy diet of fruits and vegetables extends life expectancy in women in their 70s

Obesity is a genuine problem in later life, and older adults face a particular version of it: mobility limits make exercise harder, dental and swallowing problems narrow food choices, and fixed incomes narrow them further. Low- and zero-calorie products look like an obvious solution, and diet soda is the most popular of them.

What the study found

The San Antonio Longitudinal Study of Aging followed 749 older adults over several years, recording diet soda consumption and measuring waist circumference. The results were published in the Journal of the American Geriatrics Society.

Diet soda drinkers showed substantially greater increases in waist circumference than non-drinkers — roughly three times the expansion over the study period. Waist circumference matters independently of overall weight: abdominal fat is more strongly linked to cardiovascular disease, type 2 diabetes and sleep apnea than fat elsewhere on the body.

What it does not establish

This is observational, and the obvious alternative explanation is hard to rule out: people who are already gaining weight, or who already have a diagnosis like diabetes, are precisely the people who switch to diet soda. The drink may be a marker of the problem rather than a cause of it.

Proposed mechanisms exist — effects on gut bacteria, on appetite regulation, on the learned relationship between sweetness and calories — but none is settled. What can be said fairly is that swapping to diet soda has not been shown to deliver the benefit people expect from it.

The broader point about “diet” foods

Diet soda is a specific case of a general pattern. Products marketed on the absence of one ingredient — sugar-free, fat-free, low-carb — tend to be judged healthy on that basis alone, and the substitution often turns out to deliver less than expected. For older adults the stakes are slightly different from the usual weight-loss framing: the risk is not only excess but displacement, where low-nutrition products crowd out food carrying the protein, fibre and micronutrients an ageing body needs more of, not less.

Someone eating too little protein while drinking three diet sodas a day has a nutrition problem that no amount of calorie counting will identify.

Sources

• Journal of the American Geriatrics Society — Diet soda intake is associated with long-term increases in waist circumference in a biethnic cohort of older adults: the San Antonio Longitudinal Study of Aging
• World Health Organization — Obesity and overweight
• Mayo Clinic — Belly fat: why weight loss matters

Coffee is among the most consumed drinks in the world, and one of the first things people are told to give up as they age. Some of that advice is well founded — caffeine genuinely disrupts sleep, worsens reflux, and can aggravate some heart rhythm problems. But the blanket version of it may be doing more harm than good.

Caffeine and muscle

Research presented to the Society for Experimental Biology found that caffeine improved muscle power output, including in older muscle. That matters more than it sounds: age-related loss of muscle strength is one of the main drivers of falls and of losing independence, and the ability to exercise depends on muscles being able to perform in the first place.

The effect was modest, and it does not turn coffee into a treatment. But it argues against the assumption that caffeine has nothing to offer an older body.

Caffeine and the brain — with a large caveat

Researchers at the Florida Alzheimer’s Disease Research Center found that caffeine given to mice reduced levels of proteins associated with Alzheimer’s disease in both blood and brain, and reversed memory impairment in mice bred to develop Alzheimer’s-like symptoms.

Broader observational research in humans has generally found moderate coffee consumption to be neutral or modestly favourable for overall mortality — but as always, people who drink coffee differ from people who do not in many other ways.

When coffee genuinely is a problem

• It interferes with sleep, and poor sleep in older adults contributes to falls and confusion. Late-afternoon coffee is worth questioning even if morning coffee is not.
• It is a diuretic and can worsen urinary urgency — which, for someone with mobility problems, means more risky trips to the bathroom.
• It can aggravate reflux and some arrhythmias.
• It interacts with certain medications.

Sources

• Society for Experimental Biology — Caffeine boosts power for elderly muscles
• University of South Florida Health — Caffeine reverses memory impairment in mice with Alzheimer’s symptoms
• National Institute on Aging — Healthy eating, nutrition and diet

Weight management tends to drop down the list of priorities in elder care, crowded out by more immediate conditions. There is a reasonable case that it deserves more attention than it gets — and a equally important case that the goal is not simply “less.”

What one study found

Researchers at Loma Linda University’s Adventist Health Sciences Center studied more than 6,000 men over the age of 75 and reported that a body mass index above roughly 22 was associated with shorter life expectancy — by a margin of several years at the higher end. The results were published in the Journal of the American Geriatrics Society.

CDC data has put obesity among US adults aged 65 and over at more than one third. Excess weight is an established risk factor for heart disease, stroke, several cancers and type 2 diabetes — all already common in this age group.

The other half of the picture

The original draft of this article ended by recommending weight control programs for older adults. That is where it needed a correction, because in geriatric medicine the more common and more dangerous problem runs the other way.

• Unintentional weight loss in an older adult is a red flag. It is associated with cancer, depression, dementia, swallowing problems, dental pain, medication side effects and simple inability to shop or cook — and it independently predicts mortality.
• Sarcopenia — age-related muscle loss — is a major driver of frailty and falls. Weight lost through dieting in an older adult is disproportionately muscle, which is exactly the tissue they cannot afford to lose.
• Being modestly overweight in later life is not the same risk it is at 40. Some reserve is protective during illness and hospitalization.

The reasonable position is that deliberate weight loss in an older adult is a clinical decision, made with their clinician, usually paired with protein intake and resistance exercise to protect muscle — and never a project a family member or attendant takes on independently.

Sources

• Journal of the American Geriatrics Society — Does excess body fat maintained after the seventh decade decrease life expectancy?
• CDC / National Center for Health Statistics — Obesity among older adults in the United States
• National Institute on Aging — Maintaining a healthy weight