You Are Not What You Eat – You Are What You Absorb (Part II)
Eating well isn’t enough – you also have to digest, absorb and eliminate well for optimal health
You’ve read about the importance of digestion, so it's time to look at the next step in the process of turning your food into you.
After you’ve digested your food, it doesn’t simply pass through the small intestine into your bloodstream, and then into your cells. It’s a little more complicated.
The surface area of your small intestine is larger than a tennis court, and the active cells that line it are replaced every four days. The health of the cells will determine their ability to absorb the nutrients from your digested food, as well as reject toxins that you don’t need.
Your small intestine absorbs different nutrients at different places on its vast surface area, with each place requiring different conditions to optimize this absorption.
B vitamins, minerals and fats are absorbed when the stomach acid environment is just right, and B12 is absorbed when there’s enough intrinsic factor, which is also dependent on enough stomach acid. Various bacteria and fiber are also required to increase and maximize absorption.
Some foods irritate your gut
Unfortunately, the villi, the tiny protrusions that increase the surface area of the small intestine, are very sensitive, and easily damaged by specific foods, such as fried foods, chilies, vinegar and other irritating substances such as caffeine, as well as compounds that can cause allergies, such as gluten, dairy and alcohol, as well as various types of infections.
Luckily the cells that make up the villi are some of the most easily regenerated cells in the body, so if you know how to heal them, you can help absorption immensely. Vitamin A, zinc, glutamine and butyric acid are some of these important healing compounds.
Most nutrients have to be carried across the intestinal wall into the bloodstream, to be used by the body, and only a few pass through via diffusion. Of course, nutrients are once again required to make this process efficient, so a vicious cycle will occur if these nutrients can’t be produced due to lack of absorption. Amino acids and glucose need active transportation across the intestinal wall, and are therefore the ones most frequently malabsorbed.
Foods that interfere with absorption
Preparing the foods for absorption occurs with the help of chewing properly, producing the right digestive enzymes and avoiding irritating substances, as you saw in part one. However, there are certain substances in food that can inhibit absorption or even compete with each other for absorption, in so doing reducing the nutrient content of the foods. These compounds will interfere with absorption and therefore reduce nutrient content:
- Methylxanthines in coffee, tea and cocoa
- Phytates in wheat
- Oxalates in spinach and rhubarb
- Digestive tract irritants, such as alcohol, antibiotics, painkillers, chilies and caffeine
If you suspect that you are not absorbing the nutrients from your food, you can request a stool analysis from your healthcare provider, which will highlight what your body isn’t absorbing. An intestinal permeability test is also a good indicator of what isn’t being absorbed, as it will indicate the size of the food molecules that are passing through your digestive wall.
Why you need the right bacteria in your gut
Not all bacteria are bad – in fact without friendly bacteria in your gut, you wouldn’t be able to maintain optimal health. You have about 100 trillion bacteria in your digestive tract, most being present in your colon.
They make some vitamins, digest fiber and also help you fight unfriendly bacteria, viruses and fungi. They form an integral part of digestive health, and up to 2 kg of your body weight is made up of these special bacteria.
The good bacteria are called "probiotics" or intestinal flora. There are many different kinds, but their main aims are to help fight infection by building your immunity, make certain vitamins, promote good bacteria, repair and help maintain digestive tract health, reduce inflammation as well as allergic inflammatory responses.
Fermented foods contain the friendly bacteria, so consuming unsweetened yoghurt, sauerkraut, miso and sourdough bread, if you can tolerate gluten, are some of the foods that can help to maintain these intestinal helpers.
Prebiotics are foods that feed the probiotics, keeping them healthy, and they are found in bananas, fruit, garlic, and artichokes as well as barley, onions and soybeans.
A plant-based diet will naturally provide the requirements for feeding and maintaining these important bacteria.
If your digestive system is in need of supplementing with probiotics, due to the heavy use of antibiotics, then you need to choose a supplement that has a combination of beneficial bacteria, and that has been kept refrigerated.
When they come into contact with moisture, such as they will in your stomach, they will come back to life and multiply rapidly. Follow the directions, but be aware that you may need more than the recommended dosage if your digestive tract is severely depleted of these friendly helpers, so get advice from your health care provider if you are in any doubt.
Once again stress plays a negative role in your gut
Of course, stress will also influence the absorption of your food negatively, as once again, your body is more interested in dealing with what it perceives as a threat to its survival, than absorbing nutrients. It’s therefore important that you eat when you are in a calm frame of mind, as the way that you feel while eating will influence how that food reacts in your body.
The optimal absorption of nutrients is critical for optimal health, as you are made up of the foods that you digest and absorb. Every single aspect of your health will suffer if your foods aren’t digested and then absorbed efficiently.
Delzenne NM. Oligosaccharides: state of the art. Proc Nutr Soc 2003 Feb; 62(1): 177-82.
Erasmus U. Fats that heal, fats that kill. Burnaby BC, Canada: Alive Books; 1993.
Link LB, et al. Raw versus cooked vegetables and cancer risk. Cancer Epidemiol Biomarkers Prev 2004 Sep; 13(9): 1422-35.
Ramakrishna BS. Probiotic-induced changes in the intestinal epithelium: implications in gastrointestinal disease. Trop Gastroenterol 2009 Apr-Jun; 30(2): 76-85.
Talbott S. The cortisol connection – why stress makes you fat and ruins your health and what you can do about it. CA: Hunter House Publishers; 2007.