It’s not easy to get your head around the subject of carbohydrates! Starch, monosaccharides, disaccharides, polysaccharides, simple sugars, refined sugars, glucose, sucrose, fructose, lactose…there are so many words that the lists goes on and on!
In terms of fertility, this is a crucial area of nutrition to understand because there is now evidence to show that including the right type and amount of carbohydrate in your daily diet may help improve the chances of conception, and a daily diet high in highly processed carbohydrates can affect fertility.
What exactly is a carbohydrate?
Carbohydrates are a vital macronutrient that should provide around half of our daily energy requirements (ideally around 45 percent when it comes to fertility). Fruit, vegetables, nuts, seeds, grains, and legumes, among other plant foods, provide them to us. Carbohydrates are sugars, starches, and fibres found naturally in our diet. The majority of carbohydrates are simple sugars like glucose. When many simple sugar molecules are linked together, starches and fibre are created. Our bodies break down starches to produce glucose, whereas fibre passes through our digestive tract largely undamaged, bringing toxins with it and playing a crucial part in their removal.
What are simple and complex carbohydrates?
Carbohydrates are classified as either simple or complex based on their chemical structure and how they are digested by the body. Simple carbohydrates are made up of small sugar molecules that are simple to digest by the body. Some of these sugar molecules are found naturally in food such as fruits, while others are highly processed and added to baked goods. Here’s an example of how not all carbohydrates are created equal: as, not all simple carbohydrates such as those found in fruit, are bad; instead, the focus should be on how quickly they raise blood sugar levels.
Simple, PROCESSED carbohydrates, on the other hand, are the ones to watch, as they are linked to insulin resistance, high cholesterol levels, and metabolic syndrome, all of which are diseases that may hinder conception.
Complex carbohydrates on the other hand (or ‘slow’ carbs) contain longer chains of molecules and are digested more slowly. Examples of ‘slow’ carbohydrates are foods such oats, brown rice, cooked sweet potato, beans, some fruit and vegetables, wholegrains and lentils. Slow carbohydrates also contain vitamins, minerals and fibre. This type of carbohydrates help balance the blood sugar levels making you feel less hungry.
Tools to assist you in making informed carbohydrate choices…. The Glycaemic Index (GI) and Glycaemic Load (GL).
When it comes to choosing carbohydrates and fertility, it is a good idea to think ‘slow and low’. The Glycaemic Index (0-100) ranks carbohydrates according to how quickly they elevate blood sugar levels. Pure glucose has the highest GI (with a value of 100) and is used as the comparison point for other foods.
Glycaemic load (GL), on the other hand, takes into account the amount of carbohydrate that is consumed as well as how quickly that carbohydrate raises blood sugar.
To calculate GL, divide the glycaemic index of a food by the quantity of carbohydrate it contains per serving and multiply by 100; GL = (GI x carbohydrate (number in grammes) / 100. When creating an optimal fertility diet, Glycaemic Load is more informative because it tells you how a serving of food will affect your blood sugar.
Slow carbohydrate foods (such oats, brown rice, cooked sweet potato, beans, lentils) have a lower GL than fast carbohydrate foods (like sweets, cakes, and processed foods), which cause blood sugar levels to rise and fall. As a result, eating more low-GL meals slows digestion and regulates energy release from foods and drink.
Low GL carbohydrates help to keep blood sugar levels in check by regulating sugar release. You may feel tired, irritated, and depressed if your blood sugar levels lower too much and so foods such as oats, beans, lentils etc help to keep blood sugar levels more ‘balanced’. Complex carbohydrates also aid in the appropriate absorption of tryptophan, a natural precursor to serotonin (the brain’s “feel-good” neurotransmitter).
The important take away….
A decent rule of thumb when it comes to carbohydrates is to think to yourself… Is this a whole food carbohydrate in its natural state or has it been processed?
Jorge E Chavarro, Carbohydrates and fertility: just the tip of the (fertility) iceberg, The American Journal of Clinical Nutrition, Volume 112, Issue 1, July 2020, Pages 1–2, https://doi.org/10.1093/ajcn/nqaa039
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