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Nutrition for healthy ageing

Nutrition for Healthy Ageing
Hello, my name is Maria O’Sullivan. I’m an Associate Professor in Nutrition in Trinity College in Dublin. In terms of nutrition, we’re constantly bombarded with messages around diet and health that promises everything from miracle weight loss to anti-aging. And often it’s difficult to distinguish the facts from the fiction– who is selling us false promise, and what is backed up by good sound science? In this section, we aim to highlight some of the knowns, or well-evidenced recommendations, around diet and healthy ageing, and to address a number of common myths or misconceptions. So number one, maintain a healthy weight and prevent obesity. Obesity is a modifiable risk factor for several chronic age-related diseases, including Type 2 diabetes, cardiovascular disease, cancers, and osteoarthritis.
It importantly is a modifiable risk factor, in that preventing obesity and maintaining a healthy weight and a healthy waist size are core recommendations for health. As we age, physical activity decreases, and our energy, our calorie requirements, decrease. And indeed, being more physically active in itself is a strategy for disease prevention. Number two, it’s not all about fat. And muscle really matters in healthy ageing. Skeletal muscle is not just for the young, fit, and athletic. Maintaining muscle mass is crucial in promoting function, metabolic health, mobility, and independent living. And from the age of about 40 onwards, there is a slow, progressive loss of skeletal muscle mass, at the rate of 0.5% to 1% per year.
And both physical activity and adequate protein intake are recommended to optimise skeletal muscle. So for example, an estimated 80 or 90 grammes of high-quality protein per day– which would be meat, chicken, fish, eggs, cheese, or similar– and spread into small quantities of about an ounce, or 30 grammes, across a day, is thought to be useful strategy in promoting muscle mass. Number three, what about specific vitamins and minerals? Well, while energy requirements may be decreased, vitamin and mineral requirements do not necessarily decrease. So for example, vitamin D intakes higher than recommended for the general public are recommended for people over 70 years of age. So for example, that’s about 800 units, or international units, per day.
And vitamin D, which is primarily derived from sunlight, may be suboptimal since the ability to make and metabolise this vitamin declines with age. And dietary sources, mainly oily fish and fortified foods or supplements, may be inadequate. So preventing vitamin D deficiency is important for bone health, but with newer research now suggesting roles such as in falls prevention, muscle function, as an anti-inflammatory, and of promoting brain health. But more research is required. A further example is vitamin B-12 levels. Sourced from foods of animal origin, it may decrease with age. And with a body of work now highlighting that maintaining adequate B-12 levels may be associated with better brain health.
What’s important is that current evidence, however, for either vitamin D or B-12, does not support the use of very high doses, or megadoses, over and above what’s required to prevent deficiencies, or recommended by a health care provider. Number four, healthy diet and ageing. Now, adherence to healthy eating patterns, such as the Mediterranean-style diet, is typically associated with longevity and reduced risk of age-related diseases. Indeed, newer evidence suggests that these diets may promote a healthy and diverse gut microbiome– which are the bugs in your gut– which is a rapidly growing area of research in many fields, including ageing. So let us now take a look at some popular areas of interest– detox diets. So detox diets are beneficial and anti-aging.
True, or false? False, if by detox you simply mean cutting down on the consumption of processed foods, confectionery, fat, sugar, or alcohol– for example after Christmas, or after a holiday. That’s sensible, but you don’t need any special expensive detox products. You have your own secret weapon for detox, and it’s your liver. Super foods. Super foods can be helpful in promoting healthy ageing. True or false? False, from my perspective. So from a scientific perspective, these are just foods. Some foods have higher concentrations of nutrients– the vitamins or minerals or other components, such as polyphenols or antioxidants– than others, but there’s no magic bullet.
And the so-called super foods are often costly, and the doses for the claimed benefits are often not determined. So how much do you need, a portion per day, or a truckload? And as individuals, we don’t eat single nutrients or single foods, and our health is associated with our dietary patterns over many years. So in summary, maintaining a healthy weight, being physically active, and eating a healthy diet are important. And while our diet is undoubtedly important to maintaining health in ageing, we need also to remember that food is an integral part of the social and cultural fabric of life for all ages that we share with gatherings of friends and family in celebrations and enjoy with others.

Be your own better judge. When you see a headline, news item or online report about some great new diet or food that will improve memory or prevent an array of ailments, think again.

Unquestionably, new scientific research has enormously increased our understanding of how to maintain health as we age, but never has there been so much information out there promising everything from miracle weight loss, to quick fixes and anti-ageing. Often, it is difficult to distinguish fact from fiction and to identify what is backed up by good science.

  • In this regard, scientists look for ‘sufficient evidence’ to make a reasonable judgement about diet and health. There are particular scientific approaches to conduct studies, pool findings and judge their accuracy.

But before we get weighed down in scientific jargon or lessons in statistics, here are some basic tips or questions to consider as you navigate through new discoveries and that next big thing in food, nutrition and health:

  1. Who is saying it? If it is a ‘wonder food’, then who is suggesting it is wonderful? ? Is it a credible organisation such as WHO, World Cancer Research Fund (WCRF), or a Government body? Is the recommendation based on a new published research study (bearing in mind that some studies are better than others)?
  2. Does it sound too good to be true? I think we all know the answer to that one.
  3. Mice or men? Was the study based on animals or humans? You would be surprised how many reported findings, even in the diet/nutrition field, may actually be based on animal work. And, while this kind of science is important and has been the basis of many discoveries, the application to humans cannot be assumed. Further work in humans would naturally be required.
  4. Dose matters. Consider if the report states how much or little of this food/nutrient you would need to consume to have the proposed beneficial effect. A portion per day versus a truckload …. and if you did manage to consume the truckload would that pose other (negative) consequences?
  5. We eat foods, not single nutrients and so it is our dietary patterns over longer periods of time that influence health.
  6. Cause and effect. If consuming a high level of A (e.g. a food) is associated with a low level of B (e.g. a disease) it does not necessarily mean that A caused B. People who eat more of one food may eat less of something else, or do more exercise or have different lifestyles, so the effect may be due to something else. Again, good studies should account or ‘control’ for this, but either way it doesn’t prove ‘causation’.

Because there are so many conflicting messages, in Step 3.11 we have provided some FAQs about nutrition and health.

Maria O’Sullivan is Associate Professor in Human Nutrition at Trinity College Dublin.

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