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I recently did a corporate talk on nutrition during an engineering company’s Health and Wellbeing week. I was asked a wide variety of interesting questions, so I thought it might be useful to share them along with my answers. Each of these could probably be a blog topic of their own, so I’ll try to keep my answers brief.


What is the maximum amount of coffee I should be drinking, and how much water each day?

There is no official limit to the amount of caffeine you should be consuming in a day, except for pregnant women, and children should not consume caffeinated drinks. However, caffeine is a stimulant and how this affects someone can vary person to person, so keep an eye on how much you are drinking, how you are feeling and whether you think you could benefit from cutting down if you know you drink a lot.

You should aim for six to eight glasses of fluid a day. This doesn’t have to be just water, but excludes alcohol. Be aware when drinking caffeinated drinks and alcohol that these may dehydrate you, so you might need to drink more water to compensate.


Given the levels of chemicals added to fruits and vegetables do we still benefit from eating them?

Yes. Fruit and vegetables provide significant health benefits, so we should all be aiming to consume at least five 80g portions (400g) per day. It is advisable to wash fruit and vegetables thoroughly before you eat them, to prevent food poisoning from any soil residue. If you are particularly concerned about levels of manmade fertilisers and pesticides you may choose to buy Organic produce, however there is no evidence of any difference in the nutritional quality between Organic and non-Organic produce. All EU countries are required to closely monitor and report on pesticide residue levels within foods, to ensure they are safe for consumption.


I often make veggie and fruit juices, will this affect the way that it is processed by the body?

150ml of a smoothie or juice can count towards one of your 5 A day. The smoothie will contain the same nutrients whether you eat it as a whole food or whether you eat it blended. However, the act of blending it, frees all the sugars from the cells so they are processed more quickly by the body and are more likely to have a negative effect on your teeth. Smoothies will still contain the fibrous parts of the plant, but the blender has done a lot of the work for you, so your body doesn’t have to work so hard to break down and digest the food. It will take much less time to digest and probably have less effect on your satiation/feeling of fullness than if you were to eat the foods whole. If you make a juice out of fruits and vegetables, you have removed all of the fibre, so you will not benefit from this part of the plant.


Is a vegan diet healthy?

You can have a very healthy diet as a vegan consuming a balance of nutrients, adequate protein and good fats, but you can also eat a very unhealthy vegan diet high in fat, sugar and salt and lacking in many essential nutrients.

It is possible to get all the essential building blocks of protein on a vegan diet, for example beans on toast combines the amino acids (the building blocks of protein) in legumes with those in cereals and provides all essential amino acids you need. The difficulty comes in trying to obtain enough of those nutrients that are found in greater proportion in animal products, such as iron, zinc, calcium, iodine, vitamin D and B12, and omega 3 fatty acids. Fortified dairy alternatives and fortified breakfast cereals and bread can be useful sources of calcium, iron and zinc. B12 is found in Marmite; Iodine is present in plants, but depends on soil quality, so if you are vegan you may need to consider an iodine as well as vitamin D supplement. Short chain omega 3 fatty acids can be found in some plant sources such as walnuts and flaxseed. However, these aren’t processed as effectively by the body compared to long chain omega 3 fatty acids found in fish, so you have to eat a lot to gain the same benefit.

Generally, you have to work harder to make sure you’re getting all the essential nutrients you need when on a vegan diet.


Is there anything I can eat to help me sleep?

We need to make sure we eat the building blocks that are combined within our body to make sleep inducing hormones melatonin and serotonin. This includes the amino-acid tryptophan found in most healthy protein sources including nuts, seeds, red and white meats, cheese and soya. Turkey is notoriously known for containing tryptophan perhaps explaining why we feel so sleepy after Christmas lunch!

There are a number of foods that might prevent you from getting a good night’s sleep such as foods and drinks containing caffeine including coffee and chocolate. Whatever you eat, eating late in the evening might keep you up as your body is busy digesting. A balanced meal including protein and carbohydrate with vegetables eaten before 9pm without coffee, tea or chocolate is probably the best option.


Should we as a company be stocking the fridge with full fat, skimmed milk, or soya milk?

Semi-skimmed and 1% fat milks are a good compromise, skimmed milk would be a great choice as it contains much less saturated fat compared to full fat milk. Skimmed milk still contains the same mineral content as full fat, it’s just the fat that has been removed. There is no nutritional advantage to consuming dairy alternatives such as soya, oat or rice milks. If you do opt for these, choose unsweetened versions fortified with calcium.


Doesn’t skimmed milk have more sugar than full fat?

The proportions of the macronutrients (protein and carbohydrate) might shift a little after the fat has been removed from full fat milk to make semi and skimmed milk, but it’s the water content that will increase the most as fat is reduced. You don’t need to worry about the sugar content of dairy milk as this is not added sugar.

Is it true that soya milk can reduce sperm count in men?

This is based on the fact that soya contains compounds called phytoestrogens, which act in a similar way to oestrogen in the body. Research in this area is inconclusive and other health factors such as smoking, alcohol consumption and being overweight are likely to have more of an impact. Also soya milk contains a relatively small amount of soya.  If you consume a lot of soya protein as well as soya milk, yogurt and bread etc. and you are having problems conceiving you could try reducing the amount you consume.


What time of day should I eat?

One of the latest diet crazes is time-restricted eating, suggesting that if you shorten the window in which you consume food during the day the greater the chances of losing weight. This is most likely due to the fact that you will probably consume fewer calories, with fewer opportunities to eat food.

However, I think it’s best to eat whenever fits in best with your schedule to enable you to eat as healthily as possible. Whether that means getting up earlier, so you can have breakfast at home, or eating a healthy snack at 4pm so you are not tempted by less healthy foods later on, because you don’t have your evening meal until much later. It is the total number of calories you eat in the day that is important, more than when you eat it. It is best not to eat too late, to ensure your body has done all the digesting by the time you go to bed.


What is thought to be the cause of the recent increase in wheat intolerance?

We don’t really know that there has been an increase. It could be that we’re more aware of how what we eat affects our bodies. Or it may be that the prevalence has in fact increased because we have become so reliant on one food type.

I am intolerant to wheat and I think it came about because I over consumed wheat products in my teenage years. I was very active and filled myself up on overflowing bowls of breakfast cereal, mounds of toast and pasta. I still eat a lot of carbohydrate, but I try to vary what I eat choosing a close relative to wheat called spelt, which is easier to digest, as well as other grains like oats, rye, rice and quinoa.

There is some evidence to support the hygiene theory for the noticeable increase in allergy and eczema prevalence. This theory proposes that the increase correlated to a reduced exposure to good bacteria through staying indoors, less exposure to farms and animals; our obsession with cleaning and use of antibacterial products; rise in antibiotic use and the resulting change to our gut flora.


I recently took part in a research study that told me that to stay a healthy weight I should aim to eat 1200 calories per day. This is much lower compared to the standard 2000kcal recommended for a typical women.

The estimated 2000kcal daily energy requirement is the amount required by an average female adult of average height and healthy weight (i.e. not trying to lose of gain weight). Requirements of individuals will depend on height, weight, level of activity and age. This and other guideline daily amounts (GDA) are used to help make sense of nutrition labels, but should not be used as an individual goal.


Do carbonated drinks affect the way food is processed?

As far as I am aware, the gas in carbonated drinks does not affect the way food is digested in the stomach, as long as the gas can find a way out. If the gas continues on to the intestine and becomes trapped it may cause digestive bloating and discomfort.


Is there interesting research going on in relation to the human biome and health?

The short answer is yes there is lots of research underway in the relation to gut bacteria. Research suggests that our gut flora can have a significant effect on our health and be related to conditions such as eczema, digestive cancers, inflammatory bowel conditions, obesity and metabolic diseases, immunity and cognitive issues such as depression.

As well as the benefit of high fibre diets on health, there is lots of research ongoing into the impact of types of poorly digestible carbohydrate known FODMAPs and their impact on digestive conditions such as Irritable Bowel Syndrome (IBS).


Shouldn’t we be trying to get good nutrition from food rather than relying on supplements?

Yes. There are some cases where supplements are required including pregnancy, restrictive diets, vitamin D and where deficiency is proven with a blood test. However, there are many components of food that are beneficial to us other than just vitamins and minerals, including essential fatty acids, protein, fibre and components such as phytochemicals, which would not be included in vitamin and mineral supplements, so it’s important to try and eat healthy foods to obtain all the nutrients we need to stay healthy.

Ideally my children would eat a healthy balanced diet, but we can’t seem to get them to eat healthily, so we give them a children’s multivitamin. Is this ok?

If you know they are not eating well, no matter how hard you try, then you may wish to give them a standard dose children’s multivitamin. The Department of Health recommends that all children aged six months to five years are given a vitamin supplement of vitamins A, C and D.

 Does advice around supplements apply to protein supplements?

Unless you are a high performance athlete, you are likely to be getting the protein you need from your balanced diet and don’t need to supplement it. There is no evidence that supplemental protein results in growth of muscle mass when combined with exercise and a high calorie diet, beyond the usual role of protein in the diet. Excess protein intake is excreted and not stored in the body, and high protein intakes consumed on such a diet can cause significant stress on the liver and kidneys and is therefore not advised. If you do exercise a lot and are burning extra calories then it is advisable to increase your protein intake in proportion with the rest of your diet.


Is there concern over the level of plastics within oily fish?

Some fish can contain low levels of pollutants, so there are recommendations around these. The general population should have no more than 4 portions (140g each) of oily fish per week. If you eat lots of fish, you should also restrict consumption of sea bream, sea bass, turbot, halibut and rock salmon and brown meat from crabs and not consume too often. Shark and Marlin should be restricted to one portion a week. There are no restrictions for other white fish, white crab meat or shellfish.

Is salmon or mackerel better for you?

Both are excellent sources of long chain omega 3 fatty acids. Including a variety of different types of oily fish in the diet is recommended.





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