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Ten prebiotic foods you need to know about

Ten prebiotic foods you need to know about

Ten prebiotic foods you need to know about

Gut health has become a hot topic in the world of nutrition and as research evolves it’s becoming very clear that the beneficial role of microbes found in the gut goes way beyond digestion.  The collection of microbes in your gut are referred to as your microbiome and advice about how to protect it has become commonplace.

Your gut microbiome is sensitive to your lifestyle and dietary habits; both  can either promote a good diversity of microbes in the gut or tip the balance in the opposite direction, which may have a negative impact on your health.

The foods that can have the biggest positive effect on your microbiome are those containing beneficial bacteria (probiotics) and those containing indigestible fibres referred to as prebiotics.

Your microbiome is unique like a fingerprint

The term ‘microbiome’ refers to the collection of microbes that live in and on the body, of which there are around 100 trillion, the majority of which are found in the gut.  These bugs form a protective barrier defending the body from foreign invaders, which can be harmful to health.

The microbes in your gut include bacteria, which are essential for efficient digestion.  These bacteria also help to digest antioxidant polyphenols, synthesise vitamins such as B12, D, folic acid and thiamine, and produce short chain fatty acids that provide energy to the cells of your colon helping to maintain a strong gut barrier.  Gut bacteria have also been shown to play a role in immunity and new research is starting to explore the effect on the brain with early findings linking the diversity of bacteria in your gut to mental health and obesity (via the effect on hormones that control appetite).

Like a fingerprint, your microbiome is unique, and its composition is dictated by the world around you and within you.

Cultivation is key to a healthy microbiome

It’s yet unclear what constitutes a ‘healthy’ microbiome but one thing for sure is that it takes a bit of cultivation.  If your gut becomes overrun with bad bacteria then this can upset the balance of your microbiome, which may lead to symptoms such as bloating, excessive gas, abnormal bowels, bad breath and fatigue.

A poor diet is characterised by an over-consumption of sugar and bad fats, whilst lacking in nutritious foods such as vegetables and other wholefoods including beans, pulses and wholegrains.  This type of diet has been shown to promote the overgrowth of bad bacteria in the gut  (1, 2, 3).

Medication can also impact on gut bacteria as the overuse of non-steroidal anti-inflammatory drugs (NSAIDS) and antibiotics have the potential to destroy them, which can leave your gut vulnerable and increase the risk of infection.

What are prebiotics?

No doubt you will have heard about probiotics, which are friendly bacteria found in foods such as live yoghurt and supplements.  Other foods such as kimchi, kefir and miso also contain bacteria, which are beneficial to health.

The role of prebiotics is less well understood but they’re equally, if not more important than probiotics as these indigestible fibres help the bacteria in your gut to thrive.  Probiotic supplements have the potential to be very beneficial, especially if you need to re-balance the diversity of bacteria in your gut but the same is not necessarily true of prebiotics.

There are many food sources of prebiotics, which include inulin, lignin, oligosaccharides, mucilage gums, non-starch polysaccharides (pectin and beta glucans) and resistant starches.  Foods containing these prebiotics can easily be incorporated into your daily diet and many of which you may already be eating on a regular basis. You’re more likely to be eating prebiotic foods if your diet is healthy and contains plenty of plant-based foods.

Ten top prebiotic foods to include in your diet

There are quite a few prebiotic foods, but I have chosen the ones that are more commonly eaten and easily accessed from your local supermarket.

1.Jerusalem artichoke

This vegetable is now available in larger supermarkets and is in season between October and February.  Jerusalem artichokes contain 2g of fibre per 100g and 76% comes from inulin. You can also glean a good source of thiamine (healthy nervous system and releases energy from food) and iron (healthy immune system, red blood cell production and wards of tiredness) from Jerusalem artichokes.

These are not a commonly eaten vegetable as many people are unsure how to use them.  Jerusalem artichokes have a nutty flavour and can be used in the same way as potatoes in that they can be roasted and mashed, and also work well in soups.

2.Garlic

This vegetable is closely related to onions and leeks. Garlic can form the base of many home-cooked dishes alongside onions, which means it’s easy to add to your daily diet.  Around 11% of the fibre found in garlic comes from inulin and 6% from fructooligosaccharides, which add a slight sweetness to its flavour.

3.Onions

Onions are another food that can easily be included into your daily diet as it acts as a base for many home-cooked dishes.  Around 10% of the fibre found in onions comes from inulin and 6% from fructooligosaccharides.  Onions also contain a good source of vitamin C (protects cells, maintains healthy skin and helps with wound healing) and the flavonoid quercetin, which acts as an antioxidant in the body.

4.Leeks

This vegetable is similar to garlic and onions but less commonly used.  Around 16% of the fibre found in leeks is from inulin.  Leeks are also high in flavonoids, which support the body to respond to oxidative stress.  You can also glean a good source of vitamin A (healthy immune system, eyes, skin and mucosal linings such as the nose), vitamin C (protects cells, maintains healthy skin and helps with wound healing) and vitamin K (blood clotting and healthy bones) from leeks.

You can serve leeks as a side dish, incorporate into soups or a topping for pies.

5.Apples

There’s a lot of truth in the saying about an apple a day keeping the doctor away, and this includes the health of your gut.  Around 50% of the fibre found in apples is from pectin.  This prebiotic not only benefits the health of your microbiota but has been shown to help reduce cholesterol.  Apples are also high in polyphenol antioxidants.

As well as snacking on apples you can use them to make fruit puddings, add to savoury dishes and grate as a topping for yoghurt or soaked oats.

6.Asparagus

This vegetable is now available all year round with supermarkets importing it from countries such as Peru.  To savour the best tasting Asparagus and save on food miles, you’re better to wait until the British asparagus season, which occurs between April and May.   Asparagus is not as rich in prebiotics as other vegetables with only around 5% of the fibre coming from inulin. This vegetable also contains a good source of vitamin A (healthy immune system, eyes, skin and mucosal linings such as the nose), vitamin K (blood clotting and healthy bones) and folate (healthy red blood cells and protection against neural tube defects in unborn babies).

Asparagus is delicious served on its own with a big drizzle of olive oil or topped with a poached egg for breakfast.  You can also add asparagus to pasta dishes, risottos and soups.

7.Bananas

These fruits are one of the most commonly eaten in the UK and contain small amounts of inulin.  Unripe (green) bananas are high in resistant starch and feature as an ingredient in many Caribbean dishes. Bananas are also a good source of vitamin B6 (converts food into energy and helps to form haemoglobin in red blood cells).

Bananas can be eaten as a snack, baked and used in smoothies and fruit puddings.  For something different, try adding to curries.

8.Barley

This grain is not as commonly used as others such as rice but is actually hugely versatile once you know how to use it.  Barley contains around 8g of beta glucan per 100g, which is not only good for your gut but has been shown to help reduce cholesterol. Barley also contains the minerals magnesium (converts food into energy, promotes muscle relaxation and healthy bones) and selenium (protects cells and promotes a healthy immune system).

Barley can be used in place of rice to make risotto, added to soups or salads (cooked).

9.Potatoes

Potatoes are a starchy carbohydrate as are other foods such as grains.  Starches are long chains of glucose, which the body uses for energy.  When potatoes are cooked and then cooled, they develop resistant starches, which the body is unable to break down and as such behave as prebiotics.

10.Flaxseeds

These seeds are hugely healthy and a good source of prebiotics with 20-40% of their fibre coming from mucilage gums and 60-80% from cellulose and lignin.  Flaxseeds also contain phenolic antioxidants and are a useful source of protein. You can also glean a good source of minerals from flaxseed including magnesium (converts food into energy, promotes muscle relaxation and healthy bones), iron (healthy immune system, red blood cell production and wards of tiredness), calcium (healthy bones and teeth) and zinc (converts food into energy, involved in making new cells and enzymes and helps with wound healing).  Flaxseed are also rich in omega 3 and although the conversion to more usable forms of this fatty acid in the body is poor, it’s still a useful source, especially for people following a plant-based diet.

You can add seeds to any dish and also smoothies.

If you’re eating a healthy diet, then many of the foods included will naturally take care of your gut and including the foods listed above will be especially useful to promote the health of your microbiome.

 

References

  1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3493718/
  2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4005082/
  3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4083503/
Can the food you eat really ‘boost’ your immune system?

Can the food you eat really ‘boost’ your immune system?

Can you really ‘boost’ your immune system?

As much as I love basking in the sun, I actually love the Winter.  Cosy nights in, wrapping up in Winter woollies and the celebrations of Halloween, bonfire night, Christmas and New Year are all something to enjoy.  What I don’t relish is the prospect of Winter bugs and no matter how healthy you are, they always manage to creep their way in.

As the colder months approach, it becomes more important to eat and live well to support a healthy immune system, which helps to protect us against infections.  Even the best of us are up against it during the Winter and the challenges these months present can hamper good diet and lifestyle practices.  Comfort eating, and the influence of dark mornings and early evenings offer the perfect excuse to lapse on our healthy diet and exercise regimes.

The immunity ‘boost’ conundrum 

As Winter approaches, so comes the advice on how we can ‘boost’ our immune system to ward off infectious bugs.  The idea that you can ‘boost’ your immune system is a little misleading.  This concept conjures up a false expectation of ‘supercharging’ your immune system and in some way making it invincible to anything that attempts to challenge it. The reality is that immunity involves a system and not a single entity. There are many cells of the immune system that have to respond to many different types of microbes. Pinpointing the specific cells and defining to what degree they should be increased is hugely complex and a question that’s yet unanswered by science.

Given the intricacies of the immune response, the science behind the impact of diet and lifestyle on immunity is not definitive, but research is continuing to evolve and it’s clear that maintaining a healthy lifestyle is a key part of keeping your immune system strong and healthy.

Why do we need our immune system?

You couldn’t survive without an efficient immune system, which is made up of special cells, proteins, tissues and organs that defend the body against infectious organisms and other foreign invaders through a series of processes referred to as the immune response.

Foreign invaders in the body are referred to as antigens. These are toxins or other foreign substances that induce an immune response in the body, especially the production of antibodies. One example of an antigen is the common cold virus. What makes the immune system truly remarkable is that once it has encountered an antigen, antibodies are hard coded to fight this invader should it try to attack the body again.

Can the quality of your diet help to maintain a healthy immune system?

The simple answer is yes. Exactly how diet is linked to immunity is not fully understood but is an area of research that continues to evolve.  Scientists acknowledge that malnourished people are more vulnerable to infectious diseases, which helps to illustrate the importance of diet on immunity.

Maintaining a healthy balanced diet is key and there are many micronutrients (vitamins and minerals) required to maintain the normal functioning of the immune system.  If your diet is compromised in any way through dieting or illness for example, then you may not be eating enough food or the right quality of food that allows you to glean the nutrients required to support your immune system.

Findings from the National Diet and Nutrition Survey (NDNS) have shown that amongst certain groups of the population, intakes of certain vitamins and minerals that support immunity are lacking in the diet (1).  Vitamin D plays a key role in immunity and during the Winter months a significant percentage of people have been shown to have low levels of this nutrient, given the lack of sunshine, which is the main supplier.  Minerals such as selenium, iron and zinc also play an important role in immunity and have been shown to be lacking the diet of some people as have intakes of vitamin A.  This doesn’t necessarily mean your immune system will be compromised but that attention should be paid to eating the right foods to support healthy immunity.

Foods that can support your immune system

Diet is defined by food and not nutrients.  Eating a balanced diet consisting of whole foods such as vegetables, wholegrains, lean proteins and healthy fats, will support your immune system. However, for the purposes of this blog I’m going to lay out some of the foods that contain specific nutrients that support good immunity.

Vitamin A

Orange and green fruits and vegetables contain a pigment called beta-carotene, which is converted to vitamin A in the body. Vitamin A plays an important role in maintaining a healthy immune system (2).  This nutrient helps to maintain the integrity of the mucosal cells of the gastrointestinal tract, eye and respiratory system that function as a first line of defence to infection, forming a barrier between from the environment outside the body.  Vitamin A is also important for the normal function of immune cells and the production of antibodies that respond to infections.

Iron, selenium and zinc

All of these minerals are required for the production of antibodies, which are cells of the immune system that fight infection (3, 4, 5). Findings from the NDNS survey have shown that 27% of adult women and 54% of teenage girls do not get enough iron from their diet and partnered with menstrual blood loss, this puts them at particular risk of deficiency.  Selenium intakes are also low with 38% of adults being shown to have inadequate intakes. Zinc is also lacking the diet, with 8% of adults and 17% of teenagers shown to have inadequate intakes of this mineral (1).

You can maintain good intakes of iron by eating foods such as meat, poultry, oily fish and eggs.  Plant foods such as beans, pulses, dark green vegetables and dried spices are also a good source and you can increase the uptake of iron from these foods by partnering with foods rich in vitamin C.   Selenium is found in Brazil nuts, oily fish and wholegrain foods such as brown pasta, rice and bread. Levels of selenium do vary depending on where the food has been grown and the quality of the soil. Zinc is found in meat, shellfish, eggs, beans, pulses, wholegrains, nuts, seeds and cheese.

Vitamin C

This vitamin is the one people most associate with immunity and the common cold, which is backed up by some research suggesting its effectiveness at reducing the risk and length of infection (6).  Research has shown how several cells of the immune system accumulate vitamin C and requires this vitamin to perform their task, especially T cells and phagocytes.

Most people get more than enough vitamin C in their diet, but appetite can lesson if you do get ill, which may impact on your intake. You can keep your levels topped up by eating foods such as red peppers, citrus fruits, berries, broccoli and potatoes. Vitamin C is water soluble and easily destroyed so try not to overcook vegetables and avoid soaking before cooking.

Vitamin D

Vitamin D has been shown to play an important role in the immune system by increasing the antimicrobial effect of white blood cells that fight infection (7). Low levels of vitamin D can suppress the immune system, putting you at a greater risk of viral infections. Research involving more than 19,000 people found that those with the lowest levels of vitamin D were 36% more likely to develop a common cold than those with higher levels (8).

Findings from the NDNS have shown that 30-40% of all age groups are classed as being deficient in vitamin D due to the lack of sunshine (1). Public Health England recommends everyone takes a supplement providing 10mcg of vitamin D during the Autumn and Winter.

Gut bacteria also play a role

Over 70% of immune cells are located in the gut so it makes that a relationship exists between the two. We’re beginning to understand that it’s quality and not quantity that’s key to gut health and the diversity of microbes in your gut is referred to as your microbiome.

Probiotics are bacteria that have been shown to have a positive health benefit.  Well researched strains include those from the Lactobacillus and Bifidobacterium family.  Live yoghurt is the most well-known probiotic food and contains strains such as Lactobacillus Acidophilus and Lactobacillus Casei. Fermented foods such as kimchi, kefir and miso also contain strains of bacteria that can support good gut health.

Probiotic supplements offer a way of delivering large doses of specific bacteria to the gut and may be beneficial in the prevention of upper respiratory tract infections (URTI) such as the common cold (9). The effect of probiotics on the immune system has been widely researched and certain strains have been shown to promote the production of antibodies. The same strains have also been shown to stimulate the activity of immune cells such as natural killer cells and T-lymphocytes, which help regulate immune responses.   A Cochrane Review showed that probiotics were better than a placebo in reducing the incidence and duration of a URTI (10).

Choose a supplement that contains both Lactobacillus and Bifidobacterium strains in a dose of at least 10 billion bacteria per serving.

Mushrooms are interesting too

The overall quality of your diet is more beneficial than focusing on any single food or nutrient, but mushrooms do appear to be interesting when it comes to immunity.  Not only are they one of the few foods to contain a natural source of vitamin D, but they also contain beta-glucan polysaccharides that have been shown by some studies to modulate the immune system (11).  Chinese medicine has long considered mushrooms to be medicinal and especially varieties such as shiitake.

Immunity is a hugely complex system that involves many different cells that work together to fight foreign invaders in the body.  Your diet is known to have a role to play although exactly how is yet fully understood.  Eating a balanced diet is no doubt helpful and there are certain nutrients that play a key role in maintaining the proper function of your immune system. Diet shouldn’t be defined by nutrients as food is what matters but understanding the nutrients that support your immune system help to support the importance of a balanced diet made up of a wide variety of foods.

 

References 

  1. https://www.gov.uk/government/statistics/ndns-results-from-years-7-and-8-combined
  2. https://www.ncbi.nlm.nih.gov/pubmed/11375434
  3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3173740/
  4. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3723386/
  5. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3724376/
  6. https://www.ncbi.nlm.nih.gov/pubmed/23440782
  7. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3166406/
  8. https://www.ncbi.nlm.nih.gov/pubmed/19237723
  9. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3560336/
  10. https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD006895.pub3/abstract
  11. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4684115/

 

The benefits of gut health go beyond digestion

The benefits of gut health go beyond digestion

The important role of the gut

Diet, exercise and sleep are key to good health and the prevention of disease.  The health of your gut is inextricably linked to the quality of your diet, which impacts on digestion. Besides this, research is beginning to identify how your gut may also be linked to immunity, sleep, mental health (stress, depression) and obesity, all of which can affect your health in a multitude of ways (1).

The initiative, ‘Love Your Gut Week’, starts on the 17thSeptember (2018) and highlights the importance of our digestive system to good health.

What is the microbiome?

The term ‘microbiome’ refers to the collection of around 100 trillion microbes that live in and on our body, most of which are found in the gut.  An army of microbes (including bacteria) colonise the body even before we’re born to form a protective barrier that defends against foreign invaders harmful to our health.

Your microbiome is unique like a fingerprint

Your microbiome is unique like a fingerprint reacting to the world both around and within you.  The microbes you cultivate make up the unique diversity of your microbiome. The bacteria in your gut help maintain the efficiency of your digestive system.  These bacteria also help to synthesise vitamin D, K, B12, folic acid and thiamine as well as assisting in the digestion of polyphenol compounds shown to protect the body against disease.  Gut bacteria also produce short chain fatty acids that supply energy to the cells of your colon and have been shown to play a key role in the maintenance of health and prevention of disease (2).

What can impact on the ‘health’ of your microbiome?

 Diet and lifestyle choices can impact on the diversity of bacteria found in your gut.  The ‘typical’ Western diet is characterised by an overconsumption of foods high in ‘added sugars’ and ‘bad’ fats. The impact of overeating and a lack of exercise has led to an overweight nation although the complexities of weight management are not as simple as calories in and calories out.

Being overweight is a risk factor for many diseases and the physiological effects it triggers such as inflammation are now widely recognised as being a contributory factor.  It’s often suggested that a diet overloaded with sugar and ‘bad’ fats encourages the growth of bad bacteria, but these effects don’t seem to be that clear cut. Another more straightforward explanation is that people who eat an unhealthy diet are less likely to eat the foods that support an environment that allows good bacteria to thrive such as vegetables, wholegrains and other high-fibre foods.

Five strategies to support the health of your microbiome

Whilst the overall quality of your diet can impact on the health of your gut, certain foods have been shown to be particularly beneficial in supporting the diversity of bacteria that live there.  Lifestyle factors and the use of medication have also been shown to impact on your microbiome.

1. Don’t underestimate the effects of stress

Stress is fast becoming a common side-effect of our modern lifestyle.  We all experience stress, sometimes on a daily basis, but the effects are usually short lived.  Problems can arise when stress becomes chronic, not only impacting on mental health but triggering inflammation within the body (3).  Stress can also increase the demand for certain nutrients such as the B vitamins and magnesium as well as influencing food choices that can result in a failure of the diet to provide everything the body needs.

Feeling ‘butterflies’ in your stomach or nausea are common symptoms of stress and illustrate how the brain is closely linked to the gut.  Sadness, happiness and anger are a few examples of the emotions that can affect the gastrointestinal (GI) tract, which is sensitive to such emotions.  In some cases, psychology combines with physical factors to cause pain and bowel symptoms that characterise conditions such as irritable bowel syndrome (4).  Psychosocial factors such as stress can influence the actual physiology of the gut, affecting movement and contractions of the GI tract, increasing inflammation and even making you more perceptible to infection (5).

The link between the gut and brain is referred to as the gut-brain axis and the association with gut bacteria is a new area of research.  Studies are beginning to unveil the potential impact this relationship between the gut and brain has on the microbiome.  Mental health is just one area of research and stress has been shown to alter the diversity of gut bacteria (6). These changes also appear to be amplified when stress is more severe or prolonged. In this regard, the concept of psychobiotics is being developed and refined to find ways of targeting the microbiota to help with mental health outcomes

Don’t dismiss the impact stress has on the body.  Addressing your mental health is just as important as the food you eat, exercise you take and sleep you get, all of which are intertwined.  Try exploring techniques such as meditation that has been proven to help with stress. There are many apps available that can help to teach you this practice.

2. Eat prebiotic foods in your diet

Certain fibres in foods are indigestible and commonly referred to as prebiotics.  Gut bacteria feed of these fibres, helping them to flourish and process by which they break them down (fermentation), produces short chain fatty acids.

The different types are prebiotic foods include:

  • Onions, garlic, leeks, asparagus and bananas contain inulin and fructooligosaccharides that act as prebiotics.
  • Oats and barley contain beta-glucans that act as prebiotics.
  • Starchy foods such as pasta, rice and potatoes form resistant starches (resistant to digestive enzymes) once they’ve been cooked and then cooled. Resistant starches act as prebiotics.

3. Watch your medication

Many people rely on the long-term use of medication to help manage the symptoms of their health condition. Aspirin and ibuprofen are types of Nonsteroidal Anti-inflammatory Drugs (NSAIDS) commonly used to treat inflammatory conditions such as rheumatoid arthritis, but these drugs have been shown to reduce levels of good bacteria in the gut (7).

Other medications such as antibiotics are prescribed as a short course to support the body’s ability to fight infection.  These drugs are not a friend of gut bacteria as they can wipe out swathes of both good and bad.  In certain cases, such as severe bacterial infections, they’re required to help the body recover but are of no use in fighting viral infections such as colds or flu.

Using probiotics alongside certain medications such as NSAIDS or after a course of antibiotics can help to re-balance your microbiome.

Another interesting issue surrounding antibiotics is their extensive use in the farming of food animals.  The issue is a topic of debate but eating less meat and choosing better quality meat may not only be better for your health but reduce the transmission of antibiotics through the food chain.

4. Include probiotic foods in your diet

Strains of bacteria that have been shown to have a positive health benefit are referred to as probiotics.  Bacteria from the Lactobacillus and Bifidobacterium family are some of the most widely researched strains.  One of the most common probiotic foods is live yoghurt, which contains strains such as Lactobacillus Acidophilus and Lactobacillus Casei.  These strains are also found in yoghurt ‘shot’ drinks that have become very popular. When you’re choosing live yoghurt or yoghurt products try opting for those that are low in sugar.

Fermented foods such as kimchi, kefir and miso also contain strains of bacteria that can support good gut health. These foods are now widely available in most supermarkets.

5. Take a probiotic supplement

Probiotic supplements offer a way of delivering large doses of specific bacteria to the gut.  Stick to preparations that contain well researched strains such as Lactobacillus and Bifidobacterium in a dose of at least 10 billion bacteria per serving.  To help with their transit to the gut, avoid taking with hot food and drinks or alcohol that can destroy them.

As the research linking gut bacteria to health and disease outcomes evolves, so does the potential role of probiotics supplements.  Their use and efficacy have recently come under scrutiny, but there’s still plenty of good quality research that points towards their beneficial role in health.

Prevention and treatment of diarrhoea

Bacterial strains such as Lactobacillus Rhamnosus and Lactobacillus Casei have been widely researched for their ability to prevent and reduce the severity of diarrhoea.  Research published in the Journal of the American Medical Association showed that taking probiotics helped reduce the risk of diarrhoea associated with antibiotic use by 42% (8).  Further research published in the Lancet showed that probiotics helped to reduce the risk of travellers’ diarrhoea by 8% and from all other causes in adults by 26% (9).

Immunity

The cells found in the gut are thought to make up almost 70% of the entire immune system, so it makes sense that it’s inextricably linked to immunity.  Research has shown how probiotic supplements containing certain strains can promote the production of antibodies. The same strains have also been shown to stimulate the activity of immune cells such as natural killer cells and T-lymphocytes that help to regulate immune responses.

Research has shown how probiotic supplements may prove beneficial for upper respiratory tract infections such as colds, coughs and flu. Research published in the British Medical Journal found that children who regularly took probiotics (Lactobacillus GG) had 19% fewer infectious diseases over three months compared with those that didn’t (10).

Obesity

This is new area of research and the question of whether obesity is linked to gut bacteria is not yet answered.  Data suggests that the composition of bacteria in the gut differs between people who are obese and those that are lean (11).  It’s also been shown that the typical Western-style diet rich in fat and refined carbohydrates may even increase the strains of bacteria linked to obesity (12).  Research has provided several potential reasons why the diversity of bacteria in the gut may be linked to obesity.  Certain bacteria are involved in the digestion of carbohydrates and fats (13), whilst others have the potential to increase inflammation in the body (14). Other may impact on the production of hormones that influence appetite (15).

Whilst in its early stage, this research highlights the future potential for probiotic supplements as part of personalised nutrition guidance to help in the fight against obesity.

Essential steps to good gut health

The bacteria in your gut play a role in health that’s essential to life.  New research not only helps to confirm this but is exploring the many benefits that go beyond digestion. Diet and lifestyle can both influence the diversity of bacteria in your gut and this can have a negative impact on your health.  Following a healthy balanced diet will help to maintain the health of your gut and the bacteria that reside in it as will addressing lifestyle factors such as stress. Research into the use of probiotic supplements is ever evolving but they can provide a useful way to help maintain the balance of bacteria in your gut.

Healthy gut plan

  1. Maintain a balanced diet and try to avoid foods high in sugar and ‘bad’ fats.
  2. Eat wide variety of plant-foods such as vegetables, nuts, seeds and wholegrains that are high in fibre and support efficient digestion.
  3. Include prebiotic foods in your diet – onions, garlic, bananas, oats, barley.
  4. Include probiotic foods in your diet – live yoghurt, kimchi, kefir and miso.
  5. Use relaxation techniques to address the issue of stress.
  6. Factor the use of medication into your diet and the effect on gut bacteria.
  7. Take a probiotic supplement that includes strains such as Lactobacillus and Bifidobacterium in a dose of at least 10 billion bacteria.

 

References

  1. https://www.bmj.com/content/361/bmj.k2179
  2. https://www.ncbi.nlm.nih.gov/pubmed/24388214
  3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3341031/
  4. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4202343/
  5. https://www.ncbi.nlm.nih.gov/pubmed/15740474
  6. https://www.sciencedirect.com/science/article/pii/S2352289515300370
  7. https://www.ncbi.nlm.nih.gov/pubmed/26482265
  8. https://www.ncbi.nlm.nih.gov/pubmed/22570464
  9. https://www.ncbi.nlm.nih.gov/pubmed/16728323
  10. https://www.ncbi.nlm.nih.gov/pubmed/11387176
  11. https://www.ncbi.nlm.nih.gov/pubmed/27648960
  12. https://www.ncbi.nlm.nih.gov/pubmed/28199845
  13. https://www.ncbi.nlm.nih.gov/pubmed/15505215
  14. https://www.ncbi.nlm.nih.gov/pubmed/23985870
  15. https://www.ncbi.nlm.nih.gov/pubmed/27616451/

 

 

 

Foods high in zinc

Foods high in zinc

Highest foods and greatest sources of zinc (download as a PDF Foods high in zinc)

Zinc is an essential mineral so you need to obtain it from the diet as your body cannot make it.  This mineral is involved in approximately 100 enzymatic reactions in the body and plays a role in immunity, protein synthesis, wound healing, DNA synthesis and cell division.  Zinc is also required for a proper sense of taste and smell as well as growth and development during pregnancy, childhood and adolescence.

This mineral is essential for men’s health.  Zinc plays a role in fertility by helping to improve the quality of sperm (1).  Research has shown that men with lower levels of seminal zinc had lower sperm counts as well as more abnormal sperm, which may be due to the protection of zinc against oxidative damage.

Zinc may also help to protect the health of the prostate.  Men with low levels of zinc in their diet tend to have higher chances of developing and enlarged prostate, which is known as benign prostate hyperplasia or BHP (2).

Zinc has long been associated with immunity and the common cold and some evidence points towards the benefits of this mineral in lessoning the symptoms by way of zinc lozenges (3).  Zinc also not only increases the production of white blood cells that fight infection, but also helps them fight more aggressively. It also increases killer cells that fight against cancer and helps white cells release more antibodies.  Zinc increases the number of infection-fighting T-cells, especially in elderly people who are often deficient in zinc and whose immune system may weaken with age (4).

Skin and hair health may also benefit from gleaning enough zinc from your diet.  Zinc plays an important role in overall skin health, and it may also treat eczema, psoriasis, dandruff, burns and boils (5).  This essential mineral also helps skin wounds heal faster.  Low intake of zinc has also been associated with hair loss (6)

Like many nutrients, zinc also acts as an antioxidant in the body.  Antioxidants help to reduce the damage done by excess free radicals that can increase cell aging and build up as a result of a poor diet, lifestyle and environmental factors. Antioxidants also play a role in reducing inflammation in the body.  Prolonged inflammation is thought to be at the root of many serious health conditions such as heart disease and cancer.

 

How much do you need?

UK Adult men require 9.5mg per day

UK Adult women require 7mg per day

 

Average intakes in the UK

Women consume more zinc than men

Most men and women have intakes above 100% of the RNI for zinc

9% of adult men have very low intakes of zinc

10% of teenage boys have very low intakes of zinc

 

Groups most at risk of deficiency  

The bioavailability of zinc from vegetarian diets is lower than from non-vegetarian diets because vegetarians do not eat meat, which is high in bioavailable zinc. Vegetarians and vegans also typically eat high levels of legumes and whole grains, which contain phytates that bind zinc and can inhibit its absorption.

Vegetarians can sometimes require more zinc than non-vegetarians. Certain food preparation techniques can help to reduce the binding of zinc by phytates and increase its bioavailability such as soaking beans, grains, and seeds in water for several hours before cooking them and allowing them to sit after soaking until sprouts form. Vegetarians and vegans can also increase their zinc intake by consuming more leavened grain products (such as bread) than unleavened products (such as crackers) because leavening partially breaks down the phytates; thus, the body absorbs more zinc from leavened grains than unleavened grains.

Alcoholics can have low levels of zinc because alcohol decreases intestinal absorption and increases urinary excretion of zinc.  Alcoholism can also affect food intake, which can limit the amount of zinc consumed.

Be aware that high intakes of zinc intakes can inhibit copper absorption, sometimes producing copper deficiency and associated anemia so be wary of supplement containing very high doses of this mineral.

 

How to increase your intake of zinc 

  • Add seeds as a topping to salads, cereals and porridge
  • Include plenty of dried herbs and spices to your meals
  • Include shellfish in your diet, which can be used to make salads, stews and stir-fry’s
  • Include plenty of pulses and lentils in your diet, which can be added to salads, stews, casseroles, soups or made into dips
  • Cocoa powder is high in zinc so the occasional treat of high cocoa dark chocolate is a good source of try making a cup of cocoa or homemade nut milks flavoured with this ancient ingredient
  • Try switching to wholegrains such as breads, rice and pseudo grains such as quinoa
  • Oats are high in zinc and make great breakfasts or toppings for sweet dishes such as crumbles and even savoury toppings
  • Nuts and seeds are high in zinc so try making your own healthy granola or flapjacks
  • Go veggie a few times each week and swap meat for tofu or Quorn
  • Eggs are the breakfast of champions and also make a great snack when boiled (try serving with smoked paprika, celery salt or tabasco sauce)
  • Don’t skip breakfast! Even a small bowl of your favourite wholegrain cereal can add a useful source of zinc to the diet. You can also use cereals as savoury topping

 

Foods highest in zinc (data taken from McCance and Widdowson)

 

Food Portion size (g) Mg per serving Mg per 100g
Shellfish
Raw oysters 80 47.4 59.2
Boiled lobster 100 5.5 5.5
Boiled lobster 100 2.5 2.5
Cooked mussels 100 2.3 2.3
Boiled prawns 100 2.2 2.2
Sardines canned in oil 50 1.1 2.2
Anchovies canned in oil 10 0.3 3
Meat and offal
Fried calf’s liver 100 15.9 15.9
Lamb neck fillet grilled 100 6.4 6.4
Grilled sirloin steak 100 4.3 4.3
Fried chicken liver 100 3.8 3.8
Grilled pork steak 100 2.9 2.9
Roast turkey 100 2.5 2.5
Grilled gammon steak 100 2.2 2.2
Ham 100 1.8 1.8
Grilled back bacon 50 1.6 3.1
Roast chicken 100 1.5 1.5
Pulses
Cooked aduki beans 80 1.8 2.3
Tempeh 100 1.8 1.8
Cooked chickpeas 80 1.0 1.2
Cooked red kidney beans 80 0.8 1
Cooked pinto beans 80 0.8 1
Cooked lentils 80 0.8 1
Tofu 100 0.7 0.7
Miso 30 1.0 3.3
Grains
Quinoa 180 5.9 3.3
Wheatgerm 30 5.1 17
Wholegrain rice(boiled) 180 3.2 1.8
Wholemeal bread 80 1.3 1.6
Oats 50 1.2 2.3
Oatcakes 40 1.3 3.3
Dark rye flour 30 0.9 3
Cereals
All bran 40 2.4 6
Bran flakes 40 1.0 2.5
Shredded wheat 40 0.9 2.3
Muesli 40 0.9 2.3
Weetabix 40 0.8 2
Special K 40 0.8 2
Fruit n fibre 40 0.6 1.5
Cheese and eggs
Parmesan cheese 30 1.5 5.1
Eggs 100 1.3 1.3
Edam 30 1.1 3.8
Cheddar cheese 30 0.7 2.3
Brie 30 0.6 2
Goats cheese 30 0.3 1
Nuts and seeds
Cashew nuts 25 1.5 5.9
Pecan nuts 25 1.3 5.3
Brazil nuts 25 1.1 4.2
Peanut butter 30 1.1 3.5
Peanuts 25 0.9 3.5
Tahini 15 0.8 5.4
Almonds 25 0.8 3.2
Poppy seeds 5 0.4 8.5
Pumpkin seeds 5 0.3 6.6
Pine nuts  5 0.3 6.5
Cocoa powder 15 1.0 6.9
Sesame seeds  5 0.3 5.3
Sunflower seeds 5 0.3 5.1
Vegetables
Quorn 100 7.0 7
Dried mushrooms 40 1.9 4.8
Frozen peas 80 0.7 0.9
Seaweed (nori) 10 0.6 6.4
Asparagus 80 0.6 0.7
Spinach 80 0.6 0.7
Okra 80 0.5 0.6
Brussels sprouts 80 0.4 0.5
Sundried tomatoes  40 0.3 0.8
Mushrooms 80 0.3 0.4
Parsnips 80 0.2 0.3
Endive 80 0.2 0.2
Herbs and spices
Dried chervil 5 0.4 8.8
Fenugreek 5 0.3 6.9
Dried thyme 5 0.3 6.2
Dried basil 5 0.3 5.8
Mustard seeds 5 0.2 4.7
Dried oregano 5 0.2 4.4
Cumin seeds 5 0.2 4.2
Curry powder 5 0.2 3.7
Dried cardamom 5 0.1 2.6

 

    References

  1. https://www.ncbi.nlm.nih.gov/pubmed/19285597
  2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3114577/
  3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3136969/
  4. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2702361/
  5. https://www.hindawi.com/journals/drp/2014/709152/
  6. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3870206/

 

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