As we age, changes inevitably occur in our brains just as they do in our skin, muscles, lungs, blood vessels — everywhere. While we never want to think the worst will happen to us, it would be naive to believe those wrinkles on the skin or extra huffing and puffing when climbing stairs aren’t signs that changes are happening all over, including in our brains. In this article, we take an in-depth look at the ageing brain.
This is backed up by volumes of scientific research, which has found not only clear physical changes but also decreases in cognitive abilities — significant ones in some areas and less so in others — as we age. Knowledge remains strong, for example, as do verbal skills (apart from having to reach for the right word a little more often), but there are decreases in the speed of processing information, working memory function and long-term memory processes when you compare people in their 20s to people in their 80s.
Mounting evidence points to factors like midlife obesity, dyslipidemia, diabetes, high blood pressure, cigarette smoking and cerebrovascular lesions as risk factors for developing various dementias. At the same time, preventive factors identified include regular exercise, a healthy diet, intellectually challenging work/leisure activities and an active social life, all of which can be addressed at any time of life.
The brain — or did Emily Dickinson mean the mind? — may be wider than the sky but the truth is it decreases in volume and weight with normal ageing. A figure for the shrinkage rate commonly quoted is five per cent each decade after the age of 40, with the rate rising after age 70, perhaps because some of the protective factors become more difficult and even fall away: regular exercise and the same level of social activity, for example.
These changes are not uniform in all areas of the brain, or in all people, and there may also be gender differences in which particular areas are most and least affected. One review of cross-sectional studies found that the prefrontal cortex was the most affected and the occipital cortex the least. Some studies have found the hippocampus to be the most affected by ageing, particularly in women, along with the parietal lobes, while men may see the biggest changes in the frontal and temporal lobes.
Predictably, the cognitive changes that occur with ageing can be related to the physical changes. Space limitations make it necessary to oversimplify what is a very complex subject and there are enormous variations from person to person in how particular areas of the brain are affected by ageing. Looking at the parts of the brain most and least affected by ageing, we can form a picture of the likely effects. Some physical and cognitive changes to these brain areas and abilities are thought to be consistent with normal ageing.
The prefrontal cortex is associated with executive function, which is key to things like planning, organising, co-ordinating, implementing and evaluating non-routine and novel activities in our lives. In other words, anything that’s different from the everyday habitual patterns.
The hippocampus is involved in the forming, organising and storing of memory
The hippocampus is involved in the forming, organising and storing of memory. It’s like an indexing system that consolidates information from the short-term memory to long-term memory by placing the information where it can be readily retrieved. It’s also involved in spatial orientation. The hippocampus is the first area of the brain to show effects from Alzheimer’s disease.
Parietal lobes are in two sections: one involving sensation and perception, the other concerned with processing and integrating sensory information, such as taste, temperature and touch. The frontal lobes are where everyday planning and decision-making as well as language fluency happen, while the temporal lobes are involved in hearing, listening to, processing and comprehending information.
The occipital cortex, said to be the least affected by ageing, processes information from sight. The occipital lobes tell you what your eyes are seeing.
While dementias and other neurological conditions can be said to be age-related, they are not a normal part of ageing. The good news is there is plenty we can do to minimise the effects of normal brain ageing and protect against the more sinister possibilities.
Components of healthy brain functioning
- Executive function (the ability to plan and carry out tasks)
- Remembered skills (eg driving)
- Ability to learn new skills
- Ability to live a purposeful life
“It is exercise alone that supports the spirits, and keeps the mind in vigour.” ~ Marcus Tullius Cicero, 65 BCE
Getting physical may be much more protective of brain function than doing crossword puzzles and Sudoku, according to a 2012 study carried out at the University of Edinburgh in the UK. Almost 700 septuagenarians were asked a range of questions about leisure activities and exercise. Three years later, the subjects’ brains were scanned. The researchers found that the brains of those who stayed physically active tended to be larger than those of the people who did not exercise.
The brains of the active people had larger volumes of grey matter and white matter. There were also fewer white matter lesions, which are linked to decline in thinking and memory. White matter is considered the wiring of the brain’s communication system.
Sadly, non-physical activities didn’t protect from shrinkage, meaning mental “exercise” may be less important than regular physical activity for protecting brain function into old age. Still, your 30 minutes on the treadmill could get you through the cryptic crossword faster.
A University of Pittsburgh study in the US on 120 older inactive people with no evidence of dementia had half of the subjects begin an exercise routine that included walking at a gentle pace for 30–45 minutes three times a week. The others did only stretching and toning exercises.
White matter is considered the wiring of the brain’s communication system.
A year later, brain scans showed that the hippocampus, the part of the brain associated with memory and learning, had grown slightly in the walking group but had shrunk a little in the group that did no aerobic exercise. The study also found that better physical fitness was associated with a larger prefrontal cortex.
The walkers also had higher blood levels of the brain-derived protein BDNF — believed to help with decision-making, higher thinking and learning — than the stretching group and performed better on cognitive tests. The researchers concluded that the benefits from walking equated to reversing hippocampal ageing by two years or more. In other words, 65-year-olds now had the brains of 63-year-olds simply by walking. Exercise was pronounced “one of the most promising non-pharmaceutical treatments to improve brain health”.
Other studies on both mice and humans have shown that exercise, especially between the ages of 25 and 45, boosts the chemicals in the brain that prevent degeneration of the hippocampus and that cardiovascular exercise can create new brain cells (neurogenesis) and thus enhance overall brain performance.
A small Indian study introduced yoga as an add-on lifestyle practice into the daily lives of healthy elderly subjects (aged 69 to 81). MRI scans were taken before starting the yoga and again six months later. The participants were found to have increases in grey matter in the hippocampus, meaning a significant increase in bilateral hippocampus volume.
In normal or healthy ageing, elderly people would experience an annual one to two per cent loss of hippocampus volume, so an increase is even more significant, suggesting that regular yoga practice, just like walking, could be a valuable tool in slowing brain ageing.
“The brain is like a muscle. When it is in use we feel very good. Understanding is joyous.” ~ Carl Sagan
Spanish painter Pablo Picasso was active for the best part of a century, working right up to his death in 1973. Australian artists Margaret Olley and Lloyd Rees had similarly long and productive careers. French jazz violinist Stéphane Grappelli, who died in 1997 aged 89, played well into his 80s.
Yet Nobel prize-winning author Doris Lessing, who was prolific for most of her long life, stopped working five years before her death last year at the age of 94, saying she feared her muse had dried up. “Don’t imagine you’ll have it forever,” she said. “Use it while you’ve got it because it’ll go; it’s sliding away like water down a plug hole.”
So, does creativity keep your brain young? Do artists live longer? Is there truth in the adage “use it or lose it”? Researchers say a qualified yes to all three. And the benefits of staying mentally active aren’t restricted to creative artists. Chess, gardening, cryptic crosswords, even learning a second language can affect the brain positively.
In June 2014, the journal Annals of Neurology published a new study that argued learning a second language, no matter at what age, improves intelligence levels, reading skills and verbal fluency. The study involved 853 subjects, using data from when they were 11 years old and later when they were in their 70s. Around a quarter of the participants had learned a second language before they were 18; the remainder did so later in life. The results reflected an earlier study that found bilingual individuals had delays of several years in the onset of dementia.
Of course, reading, writing and other brain-stimulating activities at any age may protect your memory later in life. Another recent US study argued that mental activity “across a person’s lifetime, from childhood through old age, is important for brain health in old age”. The research supported the idea of cognitive reserve, or the brain’s ability to cope with disease or damage, a hypothesis that argues mental activity helps delay the cognitive consequences of disease. It was recommended that people engage in “cognitively stimulating hobbies” such as photography and quilting.
In January 2014, in the journal Topics in Cognitive Science, Dr Michael Ramscar published research that suggested what looks like memory lapses are really due to the fact that older heads are so crammed with knowledge it just takes longer to retrieve the right bits. Too many tabs open in the brain’s browser…
Leaving aside obvious factors such as brain damage and Alzheimer’s, a little degeneration in the frontal lobe might even be helpful, suggests neurosurgery professor Rex Jung of the University of New Mexico in the US. In the ageing brain, mylenisation — the insulation around axons in the brain — begins to break down, loosening old fixed associations and allowing a freer flow of creative ideas.
To return to Doris Lessing, her despair at losing what she still wanted to be using may be related to a mini-stroke she suffered in her late 70s. Whereas her fellow Nobel laureate Alice Monro, now 83, after announcing her retirement from writing a few years ago, has hinted that the ideas are still flowing and her career might not be over just yet.
“The emotional brain responds to an event more quickly than the thinking brain.” ~ Daniel Goleman
Although there’s plenty of research on the relationship between social ties and mental and physical health, and we know from it that people with more social ties tend to live longer, have better general health and are less depressed, unfortunately less research has been done on the relationship of social engagement to cognitive health. The studies that have been carried out have tended to be correlational.
Longitudinal studies have found a positive correlation between being socially engaged and cognitive function, particularly when social interaction is paired with absorbing pastimes. It’s even thought that social engagement may delay the development of dementia, though it’s not clear whether one thing leads to the other. In other words, do people who age well choose socially active lifestyles or do those lifestyle choices lead to healthy ageing? Perhaps both questions get a tick.
It has been proposed by some researchers that social networks affect health through five main mechanisms — social support, social influence, social engagement, person-to-person contact and access to resources and material goods — and that these influence different health outcomes through three major pathways: behavioural, psychological and physiological.
In longitudinal studies, individuals, average age 65, who have large and active social networks demonstrate better cognitive function than those who do not.
During early and middle adulthood, most of us develop our social networks through growing families, work, sports and fitness activities and often via our children. Rather than feeling a lack of social bonds, it’s probably more common to feel you can’t keep up with so many.
...taking up some form of sport or exercise that involves other people or joining a club or group will boost brain health
There is a danger, though, of social engagement diminishing with ageing because older adults retire from the workforce, are no longer raising children and tend not to be in positions of authority. They may move to a different area for a sea or tree change or close friends or family may do so. These things can be readily countered providing one is open to developing new pastimes, considering voluntary work and becoming a “joiner”. Some people are daunted by the idea of taking up new activities while others can’t wait to finish their full-time work lives and do all the things they’ve long dreamed of doing. The trick is to think about the benefits it will bring to your life and health.
Of course, taking up some form of sport or exercise that involves other people or joining a club or group will boost brain health through the double whammy of both exercise and social interaction.
An interesting question is can social media and internet chat groups deliver the same health benefits as face-to-face interaction? While there is much debate with arguments for and against, social media may be a godsend to those who are socially isolated by distance or disability.
E-socialising can create a sense of community by being involved in online discussions and comments with a regular group of people. One survey of 2500 Americans found that, no matter whether the participants were married or single, those who used social media had more close confidants.
Positive aspects of Facebook, for example, that have turned up in surveys include: Facebook users are more trusting; they have more close relationships; they get more emotional support; they are much more politically engaged than non-users of social media. In addition, Facebook revives “dormant” relationships, reuniting friends from schooldays, former co-workers and extended family we might otherwise only speak to at weddings and funerals.
A healthy diet
“The chief function of the body is to carry the brain around.” ~ Thomas A Edison
The brain is only about two per cent of bodyweight but it greedily consumes 20 per cent of energy, so it’s vitally important to eat a diet that feeds the brain well. Of course, there’s never full agreement on what exactly constitutes a healthy diet — consider the current arguments around anti-carb, anti-grain and pro-fats (good ones at least) and the age-old tension between the benefits of vegetarian/vegan diets versus omnivore diets.
Perhaps food activist Michael Pollan’s now-famous words are the best guide: “Eat food. Not too much. Mostly plants.” In other words, eat fresh food and nothing “your great-grandmother would not recognise as food”. Keep your overall kilojoule intake at reasonable levels and make the bulk of your meals different-coloured vegetables (at least half of what’s on the plate), with small serves of protein and healthy fats, and even smaller portions of low-GI carbs. Fruit, too, is best consumed in moderation and always with the fibre — ie the whole fruit. The juice without the fibre is concentrated sugar. Coconut water is a low-sugar exception that comes to us from nature as a juice.
In addition, it’s best to eat wholefoods where possible; local, seasonal and organic where possible; and, in the case of meats, eggs and dairy, free-range and pasture-fed where possible. Stay well hydrated with good-quality water and, again in Pollan’s words, “No snacks, no seconds, no sweets — except on days that start with S.”
As for what not to have, it’s particularly important for older adults to avoid sugar and other empty carbs and to stick with moderate consumption of alcohol and caffeine, the benefits of red wine and coffee notwithstanding (see below). It’s easy to avoid both genetically modified ingredients and unhealthy fats and oils by eschewing processed foods.
Finally, always eat mindfully. Slow eating is more enjoyable eating and it helps with keeping portion sizes modest but still satisfying. You are less inclined to want seconds if you take your time and savour every mouthful.
Food for thought
If what’s good for the body is good for the brain, it follows that all fresh foods are good brain food. Some may be better than others, though.
Avocadoes. Avocadoes are rich in healthy mono-unsaturated fat, which assists with good blood flow. Better vascular health equals better brain health. With good potassium content, avocadoes are considered a blood-pressure-lowering food. They are also rich in the fatty acid oleic acid, which helps to build myelin (found on nerves and in the white matter of the brain). Neurons transport information more efficiently when insulated with myelin.
Blueberries. These and other berries contain the antioxidants anthocyanin and quercetin, phytochemicals that have been found to enhance long-term memory, learning ability and recovery from brain damage. A study of 93,000 women found that berries may reduce the risk of heart disease by 32 per cent by helping to prevent plaque buildup. A small US study found that older adults given blueberry juice scored higher on memory tests than those on placebo. Blueberries have also been shown to improve insulin sensitivity and lower blood pressure levels in pre-diabetic people without raising blood sugar. They are low in calories, high in fibre and one of the few blue-coloured foods.
Broccoli. Perhaps chief among cruciferous vegetables, broccoli is known as a “memory food” due to its high levels of choline, a B vitamin involved in brain development and cognitive functioning, including learning and memory. A Harvard study in the US of more than 13,000 women showed that the more vegetables the women ate regularly, the less age-related decline in memory, with cruciferous vegetables and leafy greens having the biggest effect. Other cruciferous vegies include cauliflower, cabbage, kale and Brussels sprouts.
Celery. Among its many impressive health benefits, celery has significant anti-inflammatory, cholesterol-lowering and blood-pressure-lowering effects. This makes it excellent for the ageing brain, as high cholesterol and high blood pressure are thought to contribute to Alzheimer’s and stroke, which lead to dementia. Celery is rich in luteolin, which has been linked to lower rates of age-related memory loss in mice and may calm inflammation in the brain. Capsicums and carrots are also good sources of luteolin.
Chickpeas. These versatile little legumes are a super source of magnesium which, apart from relaxing blood vessels, aids neuro-transmission. They combine protein for alertness with complex carbohydrate for fuel, keeping you energised and focused, and your blood sugar levels on an even keel. Chickpeas are a good source of vitamin B6, which plays a part in cognitive development through the synthesis of several neurotransmitters. A cup of chickpeas provides 70 per cent of your daily requirement of folate, too.
Coconut oil. Demonised for decades, coconut oil is now celebrated for a long list of health benefits, chief among them the ability to improve cognitive function — within 90 minutes of consuming it. A study published in the journal Neurobiology of Aging took 20 subjects with memory impairment and mild Alzheimer’s disease and scored them on a cognitive rating scale. Coconut oil improved cognitive function in all subjects soon after consuming it. Though a saturated fat, coconut oil is made up of medium-chain triglycerides (MCTs) rather than the long-chain type that are in most other fats we consume. MCTs are metabolised differently (they are not stored in adipose tissue) and can have therapeutic effects on brain disorders.
Eggs. Along with meat, eggs are an excellent source of choline, the yolks in particular. Choline is a precursor for acetylcholine, a neurotransmitter involved in memory and transporting messages between nerve cells, and therefore critical for brain health; as is folate, which is also found in eggs along with vitamin B12. Depending on what the chickens are fed — best to always choose pasture-fed — eggs are a good source of omega-3s and a perfect protein food.
Fish. Is there anyone left who doesn’t know that oily deep-sea fish such as wild salmon, tuna and sardines are loaded with the omega-3 essential fatty acids DHA and EPA? Swedish researchers found that people with the highest blood levels of DHA had a 47 per cent lower risk of developing dementia and a 39 per cent lower risk of developing Alzheimer’s compared to people with the low levels. Similarly a French study found that people with high levels of EPA had a 31 per cent lower risk of developing dementia compared to people with low levels of EPA. Scottish researchers found that people who ate oil-rich salmon, trout, mackerel or herring had an IQ level 13 per cent higher than people who never ate fish. And that people who ate fish were less likely to show early signs of Alzheimer’s.
Nuts. Nuts and seeds generally are good sources of the antioxidant vitamin E, good levels of which have been found to correspond with less age-related cognitive decline. Cashews are high in magnesium, which relaxes blood vessels, allowing better blood flow to the brain; almonds are high in riboflavin, a memory booster; and pecans and peanuts provide choline. Peanuts are also a source of folate.
Chocolate. Dark chocolate contains flavanols that make blood vessels more elastic. In a recent Harvard study, 60 people with an average age of 73 who did not have dementia drank two cups of hot cocoa a day for 30 days. They were given tests of memory and thinking skills. They also had scans to measure blood flow to the brain. The researchers found an 8.3 per cent increase in blood flow, but only in those with impaired blood flow to begin with. They associated the better blood flow with a 30 per cent boost in memory and other cognitive functioning. Don’t go self-medicating with a big block, though; beware the sugar and kilojoules. A square or two of dark, bitter chocolate a day is ideal.
Coffee. It’s possible a few cups of coffee a day could enhance the brain’s capacity to store long-term memories. In a US study, people who had a shot of caffeine after looking at a series of pictures were better at distinguishing them from similar images in tests the next day. Other studies have linked coffee drinking to a substantially decreased risk of both Alzheimer’s and Parkinson’s diseases. It has also been found that coffee can help keep the blood–brain barrier intact and have a beneficial impact on neurotransmitters.
Green tea. Researchers from the University Hospital of Basel and the Psychiatric University clinics in Switzerland gave healthy male subjects a drink containing green tea extract, then set them memory tasks. The men performed significantly better after the green tea. Using MRI, researchers analysed the effect on brain activity and found increased connectivity between the parietal and frontal cortex, which correlated with improved performance. They concluded that “green tea might increase the short-term synaptic plasticity of the brain”. The polyphenols in green tea, and indeed black tea, are believed to help protect the brain from the effects of ageing.
Red wine. Resveratrol found in red wine reduces stickiness of platelets and is thought to keep blood vessels healthy. It also raises levels of heme oxygenase, an enzyme known to protect nerve cells in the brain from damage after a stroke. A UK study concluded it’s actually the procyanidins in red wine that keeps blood vessels healthy. However, procyanidins are highest in wine made the traditional way. Analysing data from red-wine studies since 1977 and spanning 19 countries, US researchers found a statistically significant lower risk of dementia in moderate red-wine drinkers in 14 countries.
Tisanes. Tisanes, or herbal teas, are used for both their taste and expected health benefits. We all have our favourites, but two stand out for their very high antioxidant content — almost as high as green tea. Hibiscus (Hibiscus sabdariffa), rich in anthocyanins, has a blood-pressure-lowering effect. In an eight-year comprehensive study of antioxidant levels in 3139 foods, hibiscus was a top performer. As was rooibos (Aspalathus linearis), which has been found to prevent oxidative damage in the brain. Rats given rooibos tea instead of water had significantly less ageing damage in their brains than their water-drinking buddies. The 24-month-old rats given the rooibos for most of their lives had brains similar to those in five-week-old rats.
Brahmi, Indian pennywort (Bacopa monnieri). Sometimes called the Queen of Ayurveda, brahmi is an Ayurvedic herb long known in the Subcontinent for its ability to boost memory and stave off cognitive problems associated with ageing. This is somewhat supported by science. The bacosides in brahmi are thought to have a neuroprotective effect. A Wollongong University study on human memory found brahmi enhanced the capacity to retain new information, while animal studies have shown that regular doses of brahmi can improve cognitive ability and mitigate against further deterioration in Alzheimer’s disease. A Thai study also demonstrated its positive effect on neurons.
Ginkgo (Ginkgo biloba). The flavonoids and terpenoids in ginkgo combat free radicals that contribute to developing Alzheimer’s disease and vascular dementia. Studies have confirmed its effectiveness in improving memory in older people, improving blood circulation in the central nervous system and, in mice with dementia, protecting against nerve cell damage, promoting nerve cell growth and the generation of new cells. Leaf extract has been shown to protect brain cells from the accumulation of beta-amyloid associated with Alzheimer’s.
Ginseng (Ginseng panax). Ginseng root has long been valued in Oriental medicine as a panacea. It is used in particular for improving memory and concentration and for treating dementia. Research has shown it to be effective for memory impairment in mice by enhancing neurotransmitter activities that assist memory. A Chinese study found it was protective against toxicity in neuronal cells. Ginseng has also been shown to improve blood vessel and cardiac health as well as protect against some effects of diabetes.
Gotu kola (Centella asiatica). Gotu kola is highly regarded in Ayurvedic medicine as a brain tonic and promoter of longevity. Two leaves a day are believed to help you live a longer, healthier life. It also has strong anti-inflammatory properties — in the West it’s known as “arthritis plant”. In a Thai study, an extract of gotu kola enhanced the working memory in 28 elderly adults. Another study on rats showed impressive results in memory improvement after the extract was administered for 14 days. The retention of new learning in the rats treated with gotu kola was 3–60 times better than in the control animals.
Rhodiola, golden root (Rhodiola rosea). Among its many virtues, rhodiola is known as a memory herb. It has a long history of use in Russia and Scandinavian countries for fatigue and improving concentration and memory. Studies support this, showing it enhances the ability to focus, concentrate and memorise over prolonged periods by reducing fatigue. And it’s thought to increase the bioelectrical activity of the brain. A 2011 review of 11 placebo-controlled human studies supported the conclusion that rhodiola could have beneficial effects on physical endurance, mental performance and mental-health conditions such as depression.
Turmeric (Curcuma longa). Curcumin’s antioxidant, anti-inflammatory and lipophilic (ability to dissolve or attach to lipids) actions make it a promising treatment for Alzheimer’s disease. A number of studies that have attempted to establish a link between curry consumption and Alzheimer’s disease have shown there is a significantly lower incidence in India. In one study, researchers looked at the association between curry consumption and cognitive level in 1010 Asians between 60 and 93 years of age, finding that those who ate curry either occasionally or often performed better on a standard test of cognitive function than those who never ate curry or rarely ate it. A US study found that curcumin may help macrophages clear the amyloid plaques associated with Alzheimer’s disease. A Turkish study on rats showed that animals given curcumin showed markedly better cognitive function than the control group. So eat more curry. With fish. And coconut milk.
Carnosine. A protein building block naturally produced in the body, carnosine is important for healthy brain functioning. It’s a natural antioxidant and anti-glycation substance found mainly in the brain and heart. Many scientific studies have confirmed its effects, including protecting the brain from toxic metal ion reactions that lead to dementia. Carnosine levels have been found to be significantly lower in people with Alzheimer’s disease and other neurodegenerative disorders. Research has shown it can dramatically extend the lifespan of laboratory animals and human cells in vitro.
Fish oil, flax oil, krill oil. These are beneficial supplements, particularly for those who don’t eat fish, for their omega-3s. Krill oil’s reputation has overtaken that of fish oil because it’s said to contain significantly higher amounts of EPA and DHA, the antioxidant astaxanthin and small amounts of vitamins A and D. The most predominant phospholipid in krill oil is phosphatidylcholine, which is partly composed of choline. It also has a very long shelf life because it doesn’t oxidise. Some opt for flax oil for its ALAs (alpha-linolenic and alpha-linolenic acids), which theoretically convert to EPA and DHA, though in some people not enough, it’s argued.
Melatonin. Known as the sleep hormone, melatonin is also a very powerful antioxidant. Our levels of melatonin tend to decrease with ageing and have been found to be low in Alzheimer’s patients. In clinical trials and studies it has shown potential to slow or prevent the development of Alzheimer’s. In one study, people with mild cognitive impairment performed significantly better in Alzheimer’s assessment tests when treated with melatonin. In a study on mice, those treated with melatonin showed reduced oxidative stress and their markers of cerebral ageing were also reduced. It’s important to optimise your brain’s natural production of melatonin with enough good-quality sleep in a darkened room free of electromagnetic radiation.
Vitamin B12. Perhaps the key vitamin for good brain functioning, B12 supports myelin so is essential for the proper functioning of neurotransmitters. Deficiency can result in cell degeneration and atrophy leading to rapid brain shrinkage, with symptoms — even in young people — such as fatigue and neurological and psychiatric problems, which can be misdiagnosed and treated with antidepressants when simple B12 therapy might be the answer. Deficiency may be caused by low stomach acid, vegan diets, autoimmune factors, gluten sensitivity and some medications. As it is mainly present only in animal foods, eating meat, poultry, eggs, dairy and wild-caught fish is the easiest way to get B12, though fermented foods such as sauerkraut and probiotics are showing some promise. It’s important to seek guidance from your health professional on supplementation with B12.
Vitamin D. There is evidence low vitamin D contributes to oxidative damage in the brain. Vitamin D deficiency is known to be widespread among elderly people and to be associated with Alzheimer’s, Parkinson’s and heart diseases. There are receptors for vitamin D throughout the central nervous system and in the hippocampus, and vitamin D is involved in neurotransmitter synthesis and nerve growth. Studies suggest it protects neurons and reduces inflammation. Two UK studies looking at 1700 people aged 65 and 3100 men aged 40–79, respectively, assessed their vitamin D levels and cognitive function. In both, the closer to optimum their vitamin D levels, the better they performed. Those with low levels showed slower information-processing speed. Ten to 15 minutes of sun on your skin daily will help but it would still pay to have your levels tested.