Nutrients in a nutshell …
Many times when starting a diet (and not only) we tend to focus more on the foods we cut from our list and less on foods we eat.
We hear many times that it is very important to read food labels, yes it is correct, but before reading the food labels it is important for us to know a few things about the basic nutrients. This way it is easier for us to choose foods which suits better our needs and avoid the unhealthy ones.
Understanding food composition and basic nutrition mechanisms gives us a larger perspective and a better understanding of diets. If you see the big picture it will be much easier to keep a diet or establish a healthy behaviour. Also knowing the basics about the food in your plate gives you flexibility to switch between foods without changing the overall caloric value or the main nutrients ratio.
In the following article I just want to quickly present the main nutrients (the way I understand them and with the highlights I think that deserve attention) without diving to much in the subject. Feel free to read more about them from dedicated books and websites. Practically with this article I want to make you more curious about nutrients. I will try to write periodically about hot nutrition topics and debates. (in nutrition field there are always debates :) ) I also left notes about the main sources I used for this article.
Nutrients can be classified in macronutrients and micronutrients. Macronutrients, as the name suggests, are nutrients used by our body in large quantities and micronutrients are nutrients used by our body in smaller amounts.
PROTEINS play the main role in building and repairing muscle and tissues.
What are proteins made of ?
Proteins are made from amino acids.
How many amino acids do we know ?
In total there are 20 amino acids and … a few more considered special by some scientists
This amino acids combined in different variants are forming the different types of proteins.
Source : https://www.ncbi.nlm.nih.gov/books/NBK557845/
What about essential amino acids?
The 9 essential amino acids are: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine.
Source : https://medlineplus.gov/ency/article/002222.htm
Why are they called essential ?
These essential amino acids can not be produced within our body.
We need to get them from our food.
From these basic amino acids most of the remaining can be made by our body.
How can we classify proteins ?
Complete proteins which contain all essential amino acids, found in meat, fish, eggs and diary products.
Incomplete proteins which do not contain all essential amino acids are found in cereals, beans, seeds and in small amounts in vegetables and fruits.
What about vegans and vegetarians ? How can they obtain complete proteins ?
By combining foods that contain partial complete or incomplete proteins.
Calories
1 gram of proteins provides 4.1 Kcal
CARBOHYDRATES provide the energy for our body. Our body can use proteins and fats for energy but the “cleanest” fuel are the carbohydrates also called carbs or sugars.
How can we classify carbs ?
Carbohydrates can be simple and complex. The simple ones are quickly digested and the complex ones are digested slower. There is also a less digestible category of carbs called fibres which help our digestive system to run. Fibres are edible carbs but not digestible. They slow down the sugar absorption and contribute to a healthy digestion process.
So we have simple carbs (aka “fast carbs“), complex carbs (aka “fast carbs“) and fibres.
Which carbs are healthier and why ?
When eating foods which contain complex or slow carbs the sugar is slowly released and the energy is received gradually by the body for a longer period of time. The blood sugar levels is more constant and the hunger sensation does not appear so often.
For example wholemeal grains provide complex carbs and fibres but by refining them and removing the bran and germ we loose fibres and nutrients, and obtain a caloric food not so nutritious and with a faster absorption.
There are many examples of foods containing simple carbs that are healthy such as fruits and vegetables. This foods are also rich in fibres, vitamin and minerals. Eating the whole fruit instead of transform it in juice will bring us more vitamins and fibres which slow down the sugar absorption and help digestion. We just have to eat the right quantity. Milk and dairy products contain lactose which is a simple carbohydrate but they also contain complete proteins, calcium and vitamin D.
What are the foods containing simple carbs which we should pay attention or avoid ?
Soft drinks with sugar added, processed foods with sugar added, sweetened yogurts, high processed and sweetened fruit purees or canned sweetened fruit syrups with fruits…
What are the foods containing complex carbs which we should pay attention or avoid ?
Cakes, biscuits, products with refined flowers and sugar added, processed sauces…
How many carbohydrates should we eat ?
The Dietary Guidelines for Americans recommends that carbohydrates intake to stay between 45% and 65%.
Calories
1 gram of carbohydrates provides 4.1 Kcal
FATS are vital for optimal health. Fats provide energy and help our body to absorb fat-soluble vitamins.
How can we classify fats ?
Fats can be classified in saturated fats and unsaturated fats.
Unsaturated fats can be monounsaturated and polyunsaturated fats.
Which fats are healthier and why ?
Saturated and monounsaturated fats are not essential nutrients, the body can produce them.
Polyunsaturated fats are essential nutrients which our body is taking from the food.
According to many specialists, mono and polyunsaturated fats have a good influence to our health and we should pay attention to saturated fats.
A little discussion here.
We have two families of polyunsaturates essential fat acids: linoleic acids family known as Omega 6, and alpha-linolenic acids family known as Omega 3.
Although both of Omega 3 and Omega 6 are essential fats which our body needs, our modern diets contain lot more Omega 6 than Omega 3 fat acids. An optimal Omega 3 / Omega 6 ratio would be between 1:1 and 1:4 but in reality this ratio is much unbalanced in favour of Omega 6 acids. So, trying to get as many Omega 3 you can from food is recommended.
Calories
1 gram of fats provides 9.3 Kcal
VITAMINS “turn on” enzymes, which in turn make all body processes happen. Patrick Holford - ”Optimum Nutrition Bible”. Immunity, energy, hormones, brain, skin, healthy cardiovascular system - vitamins are involved in all the processes that keep our body functional. The vitamins are named with capital letters: A, B, C, D, E, K…
Vitamins can be water-soluble like B family and C, or in fat-soluble vitamins like A, D, E, K. Water soluble vitamins must be dissolved in water before they can be absorbed by the body and the amount that can not be absorbed is eliminated in urine.
Source : https://www.hsph.harvard.edu/nutritionsource/vitamins/
Like vitamins, MINERALS are essential in almost every body process. They mainly regulate and balance our body chemistry. For example:
Calcium, magnesium and phosphorus are vital for bones and teeth structure. Together with sodium and potassium these minerals are essential for nerve signals activity. Iron helps oxygen transport in the blood. Blood sugar levels are controlled with the help of chromium. Zinc plays an important role in body renewal and together with selenium help boosting the immunity system. These are a few examples of processes that involve minerals.
Calcium, magnesium and phosphorus are major constituents of the bones and together with sodium and potassium which control the water balance in the body are called “macro-minerals” because we use them in larger quantities than we use other minerals which are called “micro-minerals” or “trace minerals”.
Source : Patrick Holford - ”Optimum Nutrition Bible”.
