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The Foundations

 

A healthy balanced diet…

Chances are you’ve heard this phrase before.  Maybe in a public health message or in food advertising. Perhaps you've read it on the packaging of a health supplement that’s advised you it should be "included as part of".  But did anyone explain how to implement this balance into your diet.  Probably not. Unfortunately, without such explanation this phrase is of as much use as “eat clean” and undoubtably less catchy!

But…

Fear not. For this information exists in books and reports you’d be forgiven for never having heard of.  Because nobody has. Except for the scientists, academics and university students who have a weird passion for nutrition.  The books and reports contain the UK nutrient intake guidelines set by the Scientific Advisory Committee of Nutrition and the Department of Health.  Problem is, only weird nutrient-obsessed science folk actively "intake nutrients".  Whereas, normal people eat foods.  However, it is the combination and quantity of nutrients in the food they choose to eat that determine their health.

Here’s where this blog comes in…

The aim of this blog is to explain why these nutrients are so important, demonstrate how the guidelines can be met via food and provide ideas of how to implement it all into a diet to achieve a “healthy balance”. 

 

Unlike the other blogs on this site, this page is more of a 3 course meal than a bite sized nibble but it gives you all the foundations of nutrition.  Tuck right in if you're hungry for the facts or skip straight to dessert, if you just fancy seeing an example of how you can incorporate the functional theories into tasty meals...

Fuels (Macro-Nutrients)

 

Food is what fuels us.  Some nutrients yield energy and we need to consume them in larger amounts compared to other nutrients so that we have an adequate source of fuel. These nutrients are categorised into a group called macronutrients. The macronutrients are protein, carbohydrate and fat.  The amount/ ratio consumed of these nutrients is responsible for energy balance.

 

Energy Intake > Energy Expenditure = Weight Gain

Energy Intake < Energy Expenditure = Weight Loss

 

Food energy intake and energy expended via activity can both be measured in kilocalories (kcal) and kilojules (kJ)

1 kcal = 4.184 kJ

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"the maximum energy surplus or deficit of a healthy balanced diet should not surpass 600 kcal."

Energy balance demonstrates why it is beneficial for you to monitor the energy you consume. Unfortunately, in practice this balance is not always as simple to follow as it is on paper.  For example, when trying to gain weight as lean muscle mass, having too large of an energy surplus or consuming the wrong types of food will result in unwanted fat storage.  Additionally, having too large of an energy deficit whilst trying to burn fat can result in unwanted muscle loss. 

 

A very low calorie diet  is unsustainable and will lack the capacity for sufficient intake of essential nutrients. The is why any fat people burn whilst on "crash" type fad diets is extremely unlikely to stay off.  With this in mind, the maximum energy surplus or deficit of a healthy balanced diet should not surpass 600 kcal.

Vitamins and Minerals (Micro-Nutrients)

 

In addition to essential proteins, carbohydrates and fats all diets should include the essential micronutrients, regardless of nutritional goals.

 

"if you’ve been feeling fatigued of late or you've had some other symptoms that have given you reason to question your health, vitamins and minerals really are a great place to start your investigation."

Minerals are the inorganic elements and vitamins are the organic compounds, which are found in your food. Both are required in your diet for the maintenance of metabolic and physiological functions within your body.  They are termed micronutrients because they are required in smaller amounts compared to the macronutrients.  However, this does not make their intake any less important.  In fact, it is a deficiency in micronutrients that is considered responsible for most diet deficiency related disorders and diseases.  Even developed countries are commonly exposed to micronutrient deficiencies.  Whereas, macronutrient deficiencies are uncommon within the general populations of such countries.  Here in the UK, vitamin D deficiency is most prevalent.  Followed by Iron, especially for women of a menstrual age.  So, if you’ve been feeling fatigued of late or you've had some other symptoms that have given you reason to question your health, vitamins and minerals really are a great place to start your investigation.

 

 Most of the essential micronutrients have an intake recommendation known as a 'reference nutrient intake' or 'RNI' for short.  The RNI is the amount of a nutrient that is enough to ensure that the nutritional needs of nearly all the population (97.5%) are being met.  Some essential micronutrients are yet to be given an RNI but do have a widely accepted 'safe intake' value.   

The whole is greater than the sum of its parts...

This is a phrase that couldn’t be better suited to diet and nutrition.  Nutrient intake is far less functional when nutrients are consumed in isolation.  For example, fat soluble vitamins are exactly that.  Therefore, a supplement in pill form taken with water will offer far less bioavailability within the body than a food source that contains fat.  Some combinations nutrients work in synergy by improving absorption or by acting as precursors to biochemical and physiological functions.  Other combinations compete, thereby reducing absorption and promoting deficiency.  If you are deficient in a specific nutrient or just interested in optimising your diet, these combinations are handy to know.  

Vitamin D and Calcium

It used to be assumed the amount of vitamin D produced by sun exposure would be adequate for most of the UK population.  This is now known not to be the case.  According to the UK National Diet and Nutrition Survey, approximately 1 in 5 of the UK population are vitamin D deficient.  Since these findings the Scientific Advisory Committee on Nutrition, have determined it unsuitable to make a recommendation regarding the amount of sunlight exposure that would be required to prevent vitamin D deficiency. This is because of the number of factors that affect vitamin D production via the skin (e.g. skin colour, habitual clothing traditions and the individuals opportunities to spend time outdoors).  Subsequently, they recommend 10 micrograms daily vitamin D intake via diet.  There are few naturally rich food sources of vitamin D.  So, the incorporation of fortified foods and supplementation is encouraged for this vitamin.  However, sufficient vitamin D intake can be achieved via natural food sources alone and I will demonstrate how in this blog.

Vitamin D works in synergy with calcium. Calcitriol (the active metabolite of vitamin D) works with two hormones to maintain calcium homeostasis. Calcium is the most abundant mineral in the body and calcium homeostasis is tightly regulated. A deficiency of either calcium or vitamin D results in the reabsorption of bone tissue, of which 99% of the bodies calcium is stored.  The other 1% of calcium is needed in your blood serum for roles that include muscle function, vascular contraction and vasodilation, nerve transmission, intracellular signalling and hormonal secretion and of course bone deposition.

 

In addition to its role in calcium homeostasis, vitamin D improves calcium absorption.  Therefore, combing the two together in meals can really enhance your diet.   Some nutrients inhibit calcium absorption.  That being so, inclusion of them can be avoided in meals planned around optimising calcium and vitamin D intake. Nutrients to avoid in these meals include phytic acid, oxalic acid, caffeine and alcohol.  Natural food sources of vitamin D usually contain omega 3 fatty acids, so it makes sense to incorporate them into meals together.  Moreover, if you dislike these food sources and therefore rely on fortified foods or supplementation you will find vitamin D and omega 3 often found together in these products.

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Iron and Friends

 

Iron is not found freely in our bodies and its absorption is tightly regulated due to its highly reactive nature.  This means that iron lost from blood loss, urine and faeces can easily exceed iron uptake.  Iron-deficiency anaemia is a major problem worldwide.  In the UK, it is mainly women who are at risk of iron deficiency due to blood lost via their menstrual cycle.  According to the UK National Diet and Nutrition Survey, 54% of girls and 27% of women also have low iron intakes and are therefore at further risk of developing anaemia.  Iron can be found natural food sources in two forms.  Haem in animal products and inorganic iron salts in plant products.  The absorption of haem iron is better than that of inorganic iron salts.  Only about 1-10% of plant sourced iron is absorbed. Therefore, vegetarians and vegans are also at risk of deficiency.  These risks can easily be eliminated if some meals are aimed at optimising iron intake.

 

Vitamin C greatly enhances the bioavailability of plant sourced iron and for this reason should be incorporated into meals focused on iron.  Just like with calcium, some nutrients act as an anti-nutrient towards iron.  Thereby, reducing its absorption and bioavailability.  In fact, calcium itself acts as an antinutrient to both meat and plant sourced iron and it would be beneficial to avoid a high intake of calcium, in meals of which iron absorption is a priority.  Additionally, polyphenols and phytic acid can also reduce the bioavailability of plant sourced iron.  However, even if a meal is high in polyphenols or phytic acid, a relatively high presence of vitamin C within the meal will enable sufficient iron bioavailability.  The enhancement of iron absorption from plant sources positively correlates with the quantity of vitamin C present.  In other words, the more phytates or polyphenols present in the meal, the more vitamin C should be included.

Copper and vitamin B2 are required for iron metabolism so should be incorporated into meals focused on iron where possible.  Moreover, deficiency of either of these may be a cause of iron deficiency anaemia, although this is rare.  A deficiency of vitamin K can lead to clotting disorders which can also result in iron deficiency anaemia if losses exceed absorption of iron from the diet.

Antioxidants

Another function of vitamin C is its ability to inhibit oxidation reactions within our bodies.  Oxidation reactions produce free radicals. Free radicles cause chain reactions that can damage our cells.  Vitamin E is also an anti-oxidant.  It limits free radical damage resulting from oxidation of polyunsaturated fatty acids.  So, it’s probably no accident that vitamin E and omega 6 essential polyunsaturated fatty acids often coexist in the same natural food sources.  Although, regarded as an antioxidant, vitamin E can also have pro-oxidant actions.  At high concentrations some vitamin E can fail to bond with free radicles, penetrate further into cells and potentially cause a chain reaction itself.  I know right. Can’t win!  Well thankfully we can with Vitamin C's help.  Commonly, excess vitamin E is reduced back from its pro-oxidant like state by a reaction with vitamin C.  In other words, eating vitamin C with vitamin E would, in theory, further reduce risk of cell damaging chain reactions. 

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Electrolytes

In addition to calcium, we need to consume sodium, potassium, magnesiumphosphate and chloride. These are the minerals known as electrolytes. Electrolytes are electrically charged and help to ensure fluid levels inside and outside our cells are balanced.  They cause an osmotic gradient that is essential for hydration, nerve impulse, muscle contraction and maintaining blood pH levels.  

 

Muscle cramps, caused by an electrolyte imbalance, are something we are all familiar with.  Electrolyte imbalances can develop from having either an excess or a deficiency of electrolytes in the body.  Sodium (found in salt) is the most common electrolyte we intake too much of.  The UK National Diet and Nutrition Survey shows on average we are consuming 27% more salt than the 6 gram a day, scientific advisory committee on nutrition, recommendation.  Furthermore, this recommendation is itself high.  Our bodies only need 3 grams of dietary salt per day but this target was deemed unrealistic because of the salt content of common food products.  However, if you suffer from high blood pressure aiming for a daily salt intake <6 grams is advisable because sodium raises blood pressure.  Furthermore, potassium lowers blood pressure and the National Diet and Nutrition Survey shows on average we are consuming less than the scientific advisory committee on nutrition recommend.  Sodium and potassium are the two most important regulators of blood pressure.  Consuming less than 6 grams of salt and meeting the daily potassium recommendation of 3500 milligrams, is easily achievable if you moderate your intake of heavily processed foods.   

 

Water balance shares a close relationship with electrolyte balance.  The UK recommendation is to drink at least 1.2 L per day.

Mates of Your Metabolism 

Chromium is involved in the interaction between insulin and its cell surface receptor, and deficiency can cause impaired glucose tolerance.

 

Iodine is required for the synthesis of the thyroid hormones. Thyroid hormones regulate metabolic activity, and people with thyroid deficiency have a low basal metabolic rate.  There are many nutrients that play a pivotal role in metabolism, acting as coenzymes or cofactors, in the metabolic pathway or production of thyroid hormones. These include vitamin B1, vitamin B3, vitamin B5, vitamin B7, manganese, selenium and zinc

Pals of Protein Synthesis

Selenium and zinc also function in many other enzymes.  Some of which play pivotal roles in DNA coding and protein synthesis.  Zinc is heavily interactive with vitamin A.  Which is also needed for the regulation of gene expression and cell differentiation. Vitamin A is found in both animal products as retinol and plant products as carotenoids (mainly beta carotene). Beta Carotene also acts as an antioxidant.

Protein synthesis, of any protein, cannot proceed without an adequate supply of all the amino acids that will contribute to the primary structure of that specific protein.  Essential amino acids can be converted within our bodies to non-essential amino acids as an when they are needed for a specific protein to be synthesised.  Vitamin B6 is imperative for this conversion.  Vitamin B6 is also required for protein metabolism, which is vital for our body’s metabolic pathways.  High cooking temperatures and molybdenum are known to reduce the bioavailability of vitamin B6. However,  molybdenum is itself an essential micronutrient.

 

 

Folate and Family 

There is evidence that high intakes of folic acid (vitamin B9) may reduce the risk of ischaemic heart disease and strokes.  Vitamin B9 is also important for foetal development during pregnancy.  Both a vitamin B9 or vitamin B12 (cobalt-containing compound) deficiency will negatively affect folate metabolism because they are metabolically related.    Vegans are at risk of vitamin B12 deficiency because the vitamin is found exclusively in animal foods.  Therefore, they may want to consider using a supplement. 

Putting it Into Practice

Here is a practical application of how the nutritional theories translate into tasty food.  The following meal example week, is designed to help you explore how a mindfulness towards nutrients, can help you to meet micronutrient intake recommendations and optimise nutrient bioavailability.  Please note that in the real world, trying to intake an ideal amount of every nutrient in one week is very challenging.  So, think of this example as crash course to teach you the theory. Then in practice you can apply what you've learnt in bits and bobs.  Taking it day by day.  A little bit of mindfulness and thought towards what nutrients you're eating a day, goes a long way.

One of your daily meals could focus on Vitamin D (the most common nutrient deficiency in the UK) and Calcium uptake.  Examples of these meals are shown above in yellow.  The vitamin D recommendation is challenging to meet without supplementation and fortified foods.  However, it is possible if you eat more oily fish and eggs.  Therefore, the diet above is rich in both.

Another of your daily meals could focus on Iron (the second most common nutrient deficiency in the UK) uptake.   Examples of these meals are shown above in red.  Iron deficiency is a risk for vegans and vegetarians.  With this in mind, I have provided a red meal that is also vegan friendly. This meal is marked with a ‘V’.

The blue meals cover the remaining electrolytes, antioxidants, A and B vitamins and essential minerals to ensure metabolic and physiological functions are all running smoothly.  Incorporate one of these as your remaining daily meal to complete the ‘balance’. 

 

Let’s take a closer look at what this balance achieves…

2000kcal per day *

>30g Fibre

<5% Free sugars

<11% Saturated Fat

<2% Trans Fat 

>2 Portions of oily fish

~1.5 g, grams per kilograms bodyweight, protein **

>10 micrograms per day of vitamin D

>14.8 milligrams per day of iron ***

<6 grams per day of salt

All other essential nutrient recommendations met

* 2000 kcals per day is the accepted guideline for females.  Males could meet their 2500kcal accepted guideline by adding in healthy snacks such as fruit and nuts. Alternatively, for information on how to incorporate a more personalised approach, read the article on energy balance. 

** This is based on the average weight (70.6kg) of a female from the UK.

*** 14.8mg/ per day is the highest minimum intake recommendation for all age groups of both genders.  

 

Here’s a bibliography for anyone who’s caught the bug…

Bender, D. A. (2014). Introduction to nutrition and metabolism. Boca Raton: CRC Press.

Cheryan, M., & Rackis, J. (1980). Phytic acid interactions in food systems. CRC Critical Reviews in Food Science and Nutrition, 13:4, 297-335.

Department of Health. (1991). Dietary Reference Values of Food Energy and Nutrients for the United Kingdom. London: TSO.

Dolan, L., Matulka, R., & Burdock, G. (2010). Naturally Occurring Food Toxins . Toxins, 2, 2289-2332.

Ems, T., & Huecker, M. (2018). Biochemistry, Iron Absorption. Tampa: StatPearls Publishing.

National Diet and Nutrition Survey. (2018). NDNS: results from years 7 and 8 (combined). London: Public Health England.

Scientific Advisory Committee on Nutrition. (2003). Salt and Health. London: TSO.

Scientific Advisory Committee on Nutrition. (2011). Dietary Reference Values for Energy. London: TSO.

Scientific Advisory Committee on Nutrition. (2015). Carbohydrates and Health Report. London: TSO.

Scientific Advisory Committee on Nutrition. (2016). vitamin D and health report. London: TSO.

Scientific Advisory Committee on Nutrition. (2017). Folic acid: updated SACN recommendations. London: TSO.