Researchers at the University of Melbourne, Institute for Health & Ageing, Cancer Council of Victoria and University of South Australia, as well as the South Carolina Statewide Cancer Prevention and Control Program, University of South Carolina, and Connecting Health Innovations conducted a study to assess the prospective changes in dietary patterns and nutrient intakes among mid- to late-life women.
One of the researchers, the University of South Australia’s Prof Peter Clinton, told NutraIngredients-Asia that while the study had found significant changes for the worse in dietary patterns in older women, he was not convinced these changes had any tangible effects on the older participants.
He further said he did not think supplements or functional foods would necessarily be beneficial for older consumers, at least with regards to protein supplements for maintaining lean muscle mass.
“It's become quite standard over the last couple of decades to market liquid protein supplements to older people, but whether that makes much difference in helping them maintain lean mass, I'm not sure.
"The assumption is that more protein is better, but at a certain age, you're not going to gain any more strength. There's no reliable data to support a change in functional outcome — such as whether they are less likely to suffer fractures when they fall, which is a major concern — from taking supplements in old age."
Diet in dire straits?
Spanning a period of 14 years, the study involved a longitudinal cohort of 173 participants in the University of Melbourne’s Women’s Healthy Ageing Project (WHAP). The women were aged between 51 and 62 when the study commenced in 1998; when it ended in 2012, they were aged between 66 and 76.
The researchers used the Dietary Questionnaire for Epidemiological Studies Version 2 to assess the participants’ diets in 1998 and 2012, calculating nutritional intakes, Dietary Inflammatory Index (DII) scores, Mediterranean Diet (MD) scores, and sociodemographic and physical measures for the participants at both time points.
Subsequently, they observed that the participants’ energy intake had significantly decreased over time.
They wrote: “Energy-adjusted (i.e., energy density) total fat, saturated fat, monounsaturated fat and cholesterol intakes increased over time, while energy-adjusted and absolute carbohydrate intake decreased.”
Cholesterol intake relative to energy had also increased significantly, which was consistent with greater consumption of animal-based foods.
The researchers also observed a small increase in riboflavin intake and a significant increase of full-fat dairy products, which implied an increase in the relative intake of milk and milk products, which is a main source of riboflavin in the Aussie diet.
In addition, adherence to the Mediterranean diet had decreased over time, while DII scores had increased slightly (albeit not significantly).
At the same time, the study found significant increases in the contribution of fat to energy intake in the cohort, as well as a non-significant trend for vitamin E intake to increase and vitamin C intake to decrease.
The researchers wrote: “The changes reported are in line with a transition towards a less healthy diet and are reflected in the BMI shifting towards obesity in the context of declining physical activity and reduced energy requirements with age.”
Doubts and limitations
The researchers acknowledged that the study did not take into account participants’ socioeconomic status as a covariate. This, along with the small sample size, could have affected the results.
In conclusion, the researchers wrote: “Small changes in intakes of a range of dietary components resulted in changes towards poorer diet quality as assessed by the MD score and, though not statistically significant, the DII in these women as they aged.
“Given the importance of maintaining a healthy diet in supporting health and function with ageing, this is of concern and requires further study to identify factors associated with worsening dietary patterns and thus, facilitate targeting dietary interventions to women who need it most.”
According to Clifton, however, the best time to focus on one’s diet is between the ages of 40 and 60 — when diet has the most influence on health in old age.
He said, "I suspect that by the time you get to 65 and don't have any major health problems, trying to pursue a healthier diet probably won't make a huge difference.
"One of the reasons many older people have a poorer diet is that they may have gotten bored of cooking at home, so their protein intake decreases. I think people get lazy as they get older; they think that since they have survived so far in good health, why not relax a bit?”
He emphasised that there was unlikely to be any real cause for worry, saying that since seniors tended to be less physically active, they did not need as much energy as they used to.
"We don't really know if a 'poorer' diet has any significant effect on them at all. The study was primarily set up as a menopause study but somehow evolved into a physical study. However, we did not actually measure the effects of the participants’ dietary changes on their bodies against recommended norms."
Fellow study author Prof Cassandra Szoeke, director of WHAP, told NutraIngredients-Asia that there were many reasons for the deterioration of diet in older age, with social isolation being one of them.
"Social isolation usually means older people often just cook for one. When you cook for one, you don't have as many varieties of food or nutrients as when you cook for many.
"Another issue linked to ageing and nutrition is finance. If you have less money, you'll look for cheaper options. Also, the per head cost is cheaper when you're cooking for a family than when you're cooking for one.
“So it's not just that older people have less money (which is not always the case), but it's less economical to cook for one, so again, variation goes down."
At the same time, appetite tends to shrink with old age, and this is compounded by negative moods resulting from common occurrences such as ageism and social isolation. Furthermore, those suffering from diseases and who have to take medication tend to also have lowered appetites.
Szoeke said: "What companies can do is look at nutritional paths for older people, and work with doctors and researchers to determine what is required.
“The problem is that too often, a company simply tries to market what it already has instead of developing a product based on observational data. Industry needs to engage with consumers and researchers, so no one works in isolation.”
She added: "If you formulate something that tastes disgusting, a professor may say it works, a doctor may say it's good for you, and industry may say it has all the necessary evidence. But a consumer may try it and say it tastes bad, and not want to have it anymore.
"An industry-supported, investigation-driven and consumer-led model works best."
Source: Asia Pacific Journal of Clinical Nutrition
“Longitudinal nutritional changes in aging Australian women”
Authors: Edward Hill, et al.