Читать книгу The Doctor’s Kitchen - Eat to Beat Illness - Dr Rupy Aujla - Страница 9

Eat for your

Brain

To kick off the ‘eating to beat illness’ discussion there is simply nowhere more fascinating to start than with the brain. Our most prized possession, it controls the centres for movement, thought, emotion and all the automatic processes such as breathing and heart rate that we do not have to consciously concern ourselves with. Quite literally, it is the most advanced machine ever known to us and, unlike the latest computer or most sought-after gadget, we all have one.

Our skull houses trillions of neural synapses (the junctions between nerve cells); these carry information across different brain centres that have specific functional roles for the body. The beautiful coordination of these electrical signals determines our actions and thoughts which are generated in these centres.

Of late, however, our brains are under fire. As a medical doctor, I witness the aftermath of conditions such as dementia and strokes all too often, and the prevalence of these is increasing.¹ These conditions reveal the vulnerability of the brain and body once these centres become affected and a culmination of insults have taken place.

Dementia is now the second leading cause of death in the UK and cases are rising.² Before you assume it is a natural part of ageing and a consequence of our population living for longer, there is clear evidence to suggest the contrary. Our lifestyles drastically impact the health of our brain and this chapter will help you understand why and how we can protect ourselves and optimise our brain power.³

Loss of emotional intelligence, inhibition of thoughts, motor-control deficits, memory impairment and many more signs illustrate exactly why diseases of the brain are so life-changing. It’s the experiences of these patients that push me to highlight the impact of diet and lifestyle and how we use the tools within our control. And it starts with our plates. I haven’t written these symptoms to scare you, but rather to highlight how beautifully coordinated our brains are and the consequences of poor lifestyle choices that are preventable.⁴ We tend only to value the importance of such organs when we have lost control of their precious functions and, while you may consider these conditions to only be relevant in later age, I’m here to inform you that looking after your brain is a lifelong process.⁵ The acceptance that you ‘naturally’ lose brain function as you age is a myth⁶ and I want to show you that looking after your brain can be enjoyable and delicious!

NEUROPLASTICITY

The ability of our brain to harness new neural connections, create new brain cells and positively adapt its function in response to stimuli from our environment is a concept known as ‘neuroplasticity’. It is one of the most fascinating and promising topics I have come across in recent years, and one where food and lifestyle play a pivotal role.⁷ Previously, it was not commonly believed that cells of the nervous system could regenerate or improve their function. It was conventional thinking that after childhood development, our brains were relatively ‘static’.⁸ However, research is demonstrating that not only can we change the synapses to improve our memory and the general functioning of our brain, but it could be a useful tool in the management of conditions such as neurodegenerative disease, like dementia.⁹ As you read, you will understand how diet and lifestyle are involved in this neuroplastic process in a way that can positively impact our brain health.

BRAIN INFLAMMATION

By changing the internal environment of the body, we can create the perfect setting for the cells of our nervous system to function optimally.⁷ Oxidative stress is a topic we will visit later on (here), but our brains are particularly susceptible to an imbalance in inflammatory proteins. It has been demonstrated in many studies that an ‘inflammatory western diet’ (high in sugar, refined carbohydrates, processed foods and salt) is disastrous for brain health.^{10, 11} In addition to putting people at risk of heart disease and stroke, which all raise the risk of neurological disorders, this western-style diet promotes inflammation that could disrupt the blood-brain barrier – a protective layer that surrounds the central nervous system and is integral to the health of your brain.¹⁰

In contrast, diets high in polyphenols (the types of plant chemicals that we find in colourful fruits and vegetables) are shown to reduce oxidative stress, which may explain their benefits to brain health.¹² The Mediterranean diet contains an abundance of different polyphenols and has long been recognised as one of the healthiest diets to follow for most people.¹³ In general, it consists predominantly of plant-based proteins, plenty of pulses, quality fats from nuts and seeds as well as colourful vegetables and oily fish. The diet has been shown to reduce the incidence of vascular disease that can contribute to poor brain health, and protects against diabetes, which we know is related to declining mental ability.¹⁴ Oxidative stress and inflammation are generally reduced in those adhering to a Mediterranean style of eating, which is in part explained by the sheer number of antioxidants found in the fruits and vegetables consumed.¹⁵

MIND DIETS

As well as the potential of diet and lifestyle to reduce the incidence of neurodegenerative conditions, I think it’s also important to bring attention to some of my patients’ anecdotes following improvements to their diet and lifestyle. I regularly hear comments such as, ‘I feel clearer in my head’, ‘my mood has improved’, or even, ‘I have so much more energy these days’. I recognise that these are soft and subjective statements but – despite no concrete, clinically validated method of measuring these outcomes – it gives me further hope that positive diet and lifestyle changes could improve the lives of everyone and not just those labelled with a condition. The improvements in mental clarity and mood could potentially be explained by reducing inflammation in the brain and oxidative stress, but there’s a lot more to learn in this field.¹⁶

A specific diet, appropriately called the MIND diet, was born out of some of the research looking at the correlation of high vegetable intakes and lower rates of dementia.¹⁷ This study, plus many others, have highlighted certain ingredients as beneficial to the resilience of our brains and I’d like to bring attention to them. It is by no means a definitive list of ingredients you ‘must have’ to protect your brain, nor is it a suggestion that we can radically renew our brain cells using these foods. However, it is an introduction into how incredible and impactful our diet can be to the function of our brain.³ Hopefully this will prompt you towards a healthier perspective that could potentially offer protection to this vital organ.

+ Greens These can impact multiple systems of the body including the brain, and are one of the most important parts of a healthy diet. Ingredients such as cavolo nero, spinach, rocket and sprouts contain high amounts of phytonutrients that drastically reduce inflammation in the body.¹⁸ Inflammation is a key component of why brain processes can become disrupted leading to symptoms of fatigue and sometimes low mood.¹⁹ Dark leafy greens are also a source of fibre that could benefit the gut bacterial population found in the digestive tract, which is also involved in the regulation of inflammation in the body.²⁰ Try the Harissa Beans and Greens (see here) for a spicy and delicious way of including more greens.

+ Omega-3-rich fats Found in oily fish, nuts and seeds, plus extra-virgin olive oil. The long-chain Omega-3 fatty acids are of particular interest, as they have been shown to promote the growth of brain cells which can help maintain the adaptability of the brain.²¹ These sorts of fats are potentially key components of the brain’s neuroplastic ability. Another benefit of nuts, seeds and oily fish in the diet is the quality protein they provide. These ingredients are broken down into amino acids (the building blocks of protein) which are used for the production of neurotransmitters, the chemical messengers of the brain that are created every time your brain centres need to send signals.²² Adequate stores of good-quality protein ensure the availability of these nutrients for the production of these essential chemicals. Try the Almond and Hazelnut Lentils with Capers (see here) to get nuts into recipes.

+ Berries These have received a lot of attention for being brain protective, with good reason. They are rich sources of polyphenols, including anti-inflammatory resveratrol and quercetin, but they may also be involved in the production of brain-derived neurotrophic factor (BDNF).²³ BDNF is involved in the maintenance and survival of nerve cells and could be a critical component of protecting the brain against disease but also enhancing cognitive ability. I always have a mixture of berries in my freezer at home for convenience because they are as nutrient-dense as fresh and much less expensive.

+ Whole grains Examples of these, including red rice, rolled oats and quinoa, are great sources of antioxidants, fibre and B vitamins, which are essential for brain health.³ The brain is a sugar-dependent organ but excessive sugar that disrupts the normal mechanisms governing the control of glucose in the bloodstream has been shown to negatively impact brain cells.^{11, 24, 25}

This is why whole grains with the fibre attached are so important from the perspective of sugar control. Rather than blindly counting carbohydrates and removing anything labelled a ‘carb’ I urge patients to consider the quality of ingredients. Barley, corn and millet are nutritionally very different to breads, pasta and cakes, yet they are all lumped together under the same banner of ‘carbohydrate’. Whole grains are what we should be eating as they release sugar into the blood gradually and have not had the important nutrients stripped away from them. My Sri Lankan-style Oats (see here) are a great way of using whole grains in an unusual dish.

+ Water Perhaps the easiest to access and the most commonly forgotten ingredient of all is simply water. All too often I ask patients about their drinking habits only to discover a shockingly low amount of hydration! Discounting certain medical conditions that would contradict 2 litres of plain water a day, and excluding tea and coffee (which can actually dehydrate us), this is how much we should be aiming for. It is essential for nutrient transfer across brain cells, delivering oxygen as well as maintaining the integrity of cell structures. The simple act of hydration has been demonstrated in clinical studies to improve cognitive performance and there’s no reason why we shouldn’t all be drinking adequate amounts.²⁶ Drink for your mind.

+ Herbs and spices Most of these contain key antioxidants and phytochemicals (chemicals produced by plants) that can reduce oxidative stress.²⁷ As a general rule of thumb, using simple kitchen herbs like rosemary, basil, oregano and mint in your cooking is a great way to reduce inflammation and improve the enjoyment of food. Certain chemicals labelled ‘adaptogens’ or nutraceuticals, including ashwaganda, curcumin and gingko (to name just a few), have been given a lot of attention in the press over recent years, claiming to boost brain health with regular consumption. While I welcome greater research into compounds that are safe and well tolerated, the biggest impact on brain health is not going to come from a nutraceutical pill. I wouldn’t like anyone to believe that simply taking supplements in isolation is the best way to protect your brain. It’s going to be your plate and lifestyle that has the biggest impact.

LIFESTYLE 360

I could talk extensively about micronutrients, including vitamins E and D, or the power of individual phytochemicals, but this would neglect the importance of ‘food synergy’. We don’t eat nutrients in isolation and I’m a firm believer of an integrated dietary approach. By overanalysing single elements of our diet we miss the wider picture about the combinations of food we consume and how difficult it is to tease out what’s having an impact. We need to experiment with new and delicious ingredients but in addition, the synergistic effect of lifestyle alongside diet is a powerful combination to be reckoned with.

+ Mental training and stimulation These have been observed to increase a type of material in the brain called ‘grey’ matter that makes up parts of the brain involved in emotion, coordination and perception.²⁸ You don’t have to just do Sudoku or mathematical exercises – meditation and mindfulness regimens have also been shown to demonstrate increases in grey matter.²⁹ Playing a musical instrument, singing or any activity that focuses attention may lead to benefits and are worth the time investment to keep your brain healthy.

+ Chronic stress It has been shown that a high level of stress induces structural changes in the brain, which suggests our emotions are potent modulators of our brain’s anatomy.^{30, 31} In clinic, I emphasise the need for simple stress-relieving strategies, such as yoga, deep breathing and meditation, that heighten neural activity in the brain’s pleasure centres and improve our tolerance to stress.³² These powerful tools are accessible to everybody and, if taught appropriately, research shows can be very effective.

+ Exercise High intensity interval training (HIIT) and endurance exercises reduce the incidence of cardiovascular disease, which would ultimately reduce the likelihood of cognitive decline. But exercise itself also induces the production of ‘neurotrophic’ factors that enhance nerve cell generation and protect against shrinkage of the brain that occurs as we age.³³ Our bodies are designed to move constantly, but I find that many patients are confined to their desks in their working environments. Whether it’s a case of getting a standing desk or taking the stairs, I advise to try to move as much as possible throughout the day – exercise is not confined to the gym. Your brain will thank you for it.

+ Sleep Sleeping to both protect and greatly enhance brain function is the lowest hanging fruit, yet few of us practise good sleep hygiene. The constant stimulation from TV platforms and mobile electronic devices creates an environment associated with disrupted sleep. During sleep your brain’s lymphatic system (the system that removes toxins and waste products as a result of normal cellular processes) gets to work to clear debris that can impact the functioning of your nerve cells.³⁴ There is a clear link between poor sleep and a higher likelihood of cognitive decline, and on the other side of the spectrum, boosted cognitive performance when you are well rested. Getting a good quality 8–9 hours of rest per 24 hours is one of the simplest ways to boost brain health. Make yourself a promise: try it for 7 days and monitor how you feel. It will revolutionise what you prioritise.

By employing all these tactics we can positively impact our brain on multiple levels. We have the power with our diet to reduce inflammation, stimulate brain growth factors, promote neuronal cell production, reduce oxidative stress and improve many other processes that we have yet to discover. As well as all these dietary and lifestyle changes being protective, the aforementioned activities are also being considered in management to improve outcomes or prevent further decline in patients to good effect. This is where we need to invest more of our time and resources, but I’m making this vital information accessible to you right here. Don’t wait for the prescription pad. Take advantage of these points and start looking after your brain health right now. As you’ll discover in all the other chapters in this introduction, eating and living well doesn’t solely effect your brain health, but rather your entire ecosystem.