I heard someone make the statement recently that, “we have only one vehicle to take us through this world, that is, our body and therefore we must take care of ourselves.” This is absolutely right. But taking care of yourself does not just refer to physical health, but also, spiritual, social, emotional and occupational health. Health, as you will learn, is more than just the absence of disease, but actually living well.

One of the best ways to start taking care you yourself is to eat right and exercise. A lot of common diseases are a direct result of bad eating habits. The leading causes of death in the US are heart disease and cancer, both of which can be linked to diet. Other food related diseases in the top 10 cause of death in the US are diabetes and stroke, which again, are also linked to how we eat.

Getting the right amount of nutrients is important in maintaining good health. There are six groups of nutrients. These include carbohydrates, lipids, proteins, vitamins, minerals and water. The first three are referred to a as macronutrients since they are needed in large amounts. Vitamins and minerals are referred to as micronutrients since they are required in much smaller amounts.

The macronutrients provide us with energy, especially carbohydrates, which is generally our main source of energy. The energy that we get from the food we eat is referred to as kilocalories. This is equivalent to 1000 calories, but we generally just use the word Calories with a big ‘C’ to refer to kilocalories. So 1 kilocalorie = 1000 calories = 1 C. We get 4 C per gram of carbohydrates that we eat, 4 C per gram of protein we eat, and 9 C per gram of lipids that we eat. Alcohol also provide energy, exactly 7C per gram, but it is not considered a nutrient.

Protein is a good energy source, but its primary function is repair and building of muscle. It is also involved in many metabolic functions. For example blood, hormones, enzymes and the body’s defence system are all made up of proteins.

Lipids are either fats or oils. If the lipid is solid at room temperature, it is a fat. If it is liquid at room temperature, it is an oil. Lipids provide a backup source of energy. It also helps in absorbing certain vitamins, and it insulates our body.

Vitamins are either fat soluble or water soluble. The fat soluble vitamins spells A-D-E-K. I normally picture a fat guy relaxing on the deck of a cruise ship, to remember this. Vitamin B and C are water soluble. Vitamin B is not a single vitamin but a whole complex of 8 different vitamins, that is, B1, B2, B3, B5, B6, B7, B9, and B12.

Minerals are individual elements that are absorbed directly into the body. They are classified as either major or trace. They are major if we need >100 mg/day and trace if we need <100 mg/day. The major minerals are worth memorizing. They are sodium, potassium, chlorine, calcium, phosphorus, magnesium, and sulphur. To remember them you can use the mnemonic: “Salty potato chips contain plenty more salt”.

Salty – Sodium

Potato – Potassium

Chips – Chlorine

Contain – Calcium

Plenty – Phosphorus

More – Magnesium

Salt – Sulphur

So, how do we know what and how much to eat to be healthy? The Current Dietary Intake Recommendation can help answer this question. This is a dietary reference system that was established as a reference for healthy people to prevent diseases and to improve their health. It consists of six values:

  1. Estimated Average Requirement (EAR): This is the amount of nutrients that would be needed to satisfy the dietary need of half of a given population. So let’s say we give a certain population a certain nutrient. Exactly 50% of them would be satisfied and the other 50% would not be satisfied.
  2. Recommended Dietary Allowance (RDA): This is the amount of nutrients that would be needed to satisfy the dietary need of the up to 97-98% of a given population. Again, let’s say we give a certain population a certain nutrient. Exactly 97-98% of them would be satisfied and the other 2-3% would not be satisfied.
  3. Adequate Intake: This is the average daily intake of a nutrient that is considered to be adequate for good health. This value is normally used when there is no RDA available
  4. Tolerable Upper Intake Level (UL): I refer to this as the upper limit. It is the maximum amount of a nutrient that can be safety consumed. This means that if you exceed this amount it may be toxic to your body.
  5. Estimated Energy Requirement (EER): The average total number of calories that must be eaten to maintain a healthy body weight.
  6. Acceptable Macronutrient Distribution Range (AMDR): This is the distribution  of macronutrients needed in your diet in order to maintain good health. It is based on the percentage of daily calories eaten. For adults this is:
    1. 45-65% carbohydrates
    2. 20-35% fats
    3. 10-35% proteins

So, how you tell if your body is getting all the nutrient it needs? Health professionals use different tools to determine our nutritional status. For example:

  1. They may check our vital signs e.g. pulse, blood pressure, body temperature, respiration rate, blood, urine.
  2. They may look for external signs e.g. tongue, eyes, finger nails, hair and skin
  3. They may take anthropometric measurements such as height, circumference of the head, limbs, and waist, and compare it with similar individuals to see how “normal” you are
  4. They may conduct health questionnaires e.g. asking you about past illnesses, drug use, exercise, and diet.

The results of health assessment can conclude that you are undernourished. You can be undernourished if you are eating too little, or your body is not absorbing enough nutrients. When you are not eating enough, your nutrient deficiency is called a primary deficiency. If you are eating enough, but your body is not absorbing what it needs, we call that a secondary deficiency.

A health assessment may also conclude that you are overnourished, which generally means that you are eating too much.

For the most part, we have control over our health by simply making the right choice of what we eat. Today there is a lot of interest in the field of nutrigenomics. This is the principle that certain nutrients can switch on and off certain genes. So, can you imagine taking a supplement that can turn off cancer genes or turn on a gene that is responsible for boosting the immune system, or resisting certain diseases? This is an amazing possibility. In the meantime, though, there are no short cut to eating well. So commit to eating well so that you will live well. As Hippocrates said, “let food be your medicine and your medicine be your food”.  

Reference: Thompson, J. L., Manore, M. M.  & Vaughan, L. A. (2017). The Science of Nutrition (4th ed.). San Francisco, CA: Pearson Education.

Courtney Simons
Courtney Simons is a food science professor. He holds a BS degree in food science and a Ph.D. in cereal science from North Dakota State University.
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