Understanding Bioavailability

If you try to learn about folic acid and folate, you will eventually run across the term ‘bioavailability’. Specifically, many articles on folic acid or folate say that folic acid has a higher bioavailability than folate. What does bioavailablity mean? How does it affect you? And does it matter for people with MTHFR anomalies?


What is bioavailability?

Digestion is the process of breaking down food so it can be absorbed and used by the body. Acids in the stomach and other chemicals in the intestines turn a bite of spinach, a vitamin supplement, or a handfull of french fries into basic nutrients, vitamins and carbohydrates that can be absorbed into the body through the intestines.

During this process, many of the nutrients and chemicals that make up our food are split into smaller chemicals or changed in other ways. Some nutrients or chemicals don’t get absorbed – they pass through the intestines and are carried out as wastes. This means that sometimes you can eat what should be enough of a nutrient, but still not get enough of it.

In addition to whether or not a nutrient or chemical gets absorbed into the body, different chemicals are absorbed into the body at different rates. This is why some medicines take hours or days to take effect – if they are absorbed slowly, you won’t see any benefit until enough has been absorbed to begin making a difference.

Bioavailability is the combination of how much of a nutrient gets absorbed, and how quickly it gets absorbed. However, when talking about nutrients like folic acid and folate, bioavailability mainly refers to how much gets absorbed. So when an article talks about folate having less bioavailability than folic acid, it means that if you take 100 mg of folate, and 100 mg of folic acid, your body will actually get more folic acid than folate.


How Does Bioavailability Affect Me?

For the most part, bioavailability of any nutrient or medicine won’t affect you. The recommended daily amounts of nutrients take into account their bioavailability, so as long you take the recommended amount, you should get the right amount of the nutrients actually in your bloodsteam. Doses for medicine are also based on bioavailability.

Bioavailability does vary a bit from person to person – things like age, gender, diet and lifestyle can have an impact on how much of a nutrient your body actually absorbs. For this reason, the general RDA for a nutrient is a bit higher than most people actually need, so people with lower bioavailability for certain nutrients can still get enough. If you want to be sure you are getting enough of a nutrient, you can check out the specific recommended intake for your demographic or talk with a nutritionist.

When you are making sure you get enough folates, bioavailability becomes more important. The RDA for B9 is set based on folic acid. If you are getting most of your B9 through folates in your food, you need to take more than the RDA for folic acid in order to get enough. How much more? No one really knows. Studies on folate bioavailability have had a wide range of results. This is probably because different folates have different bioavailability rates, and because diet has a huge impact on how your body absorbs folates.

There are other issues with getting enough folates, but as far as bioavailability goes its probably a good idea to try and get at least twice as much folate as the RDA for folic acid.


How is Bioavailability Important for People with MTHFR Anomalies?

For people with MTHFR anomalies, natural folates that their bodies can use properly are often a better source of B9 than folic acid. The lower bioavailability of folate, plus other problems with folate intake, can make getting enough folate challenging. It is very important for people with MTHFR anomalies who choose to get their B9 through folate know that they need to get folate than the RDA of folic acid, and how to change their diets to maximize their folate intake.

Glutathione and Heavy Metals

As you probably know, heavy metals are usually not things that belong in the human body. There are a few heavy metals that we need a very, very small amount, but most heavy metals quickly make people sick if they get inside the body. Luckily, heavy metals are not naturally common in the environment.

When heavy metals do get into the body, the body has several ways to defend itself. These defenses don’t work against large amounts of heavy metals, but they can protect us from moderate exposure. One of the most important defenses the body has is called glutathione.

Glutathione is a tripeptide (molecule made of three amino acids) that attaches itself to some heavy metals. This is called ‘binding’. Once glutathione has bound a piece of heavy metal, the liver is able to clear the heavy metal from the body. Glutathione binds cadmium, lead, iron, and mercury.

If a person is exposed to high levels of heavy metals, such as when working in a factory that handles heavy metals, eating lots of fish that are high in mercury, or living in a home with lead paint, the glutathione will not be able to keep up with the amount of heavy metal in the body. When this happens, the heavy metals begin to make the person sick. This is known as heavy metal toxicity, or sometimes heavy metal poisoning.

On the other hand, when something interferes with glutathione a person may develop heavy metal toxicity from small amounts of heavy metals. MTHFR anomalies lower glutathione levels, leaving people who have them vulnerable to heavy metal toxicity.


More on glutathione

More on heavy metals

MTHFR, Oxidative Stress and Glutathione

Glutathione and MTHFR are both important parts of the body’s system for maintaining homeostasis. The complex way the biochemicals of the body interact, means that a problem with one important biochemical will often affect others. In the case of MTHFR anomalies, the inability of the MTHFR enzyme to do its job effectively increases the work load for glutathione, with less than pleasant consequences.


MTHFR Anomalies Create Oxidative Stress

Oxidative stress is damage to the cells of the body by free radicals. Many diseases associated with aging are caused by oxidative stress, as are a number of other health problems. People who have MTHFR anomalies have high levels of oxidative stress.

This is because MTHFR anomalies cause high levels of homocysteine, and homocysteine creates the free radicals that cause oxidative stress.


Oxidative Stress Lowers Glutathione Levels

Glutathione is one of the body’s most powerful anti-oxidants. One of glutathione’s main jobs in the body is to seek out and neutralize free radicals before they can do any damage. Glutathione also helps repair cells and DNA that have already been damaged by free radicals.

When there are more free radicals (which is another way of saying ‘high oxidative stress’) glutathione gets used up faster than usual. If it gets used up fast enough, the body isn’t able to keep up and glutathione levels drop. Then, free radicals are able to damage cells throughout the body, creating the symptoms of oxidative. Low glutathione levels also mean there isn’t enough available to repair damage to cells or help with the other things the body uses it for, like clearing heavy metal.


MTHFR anomalies → high homocysteine → more free radicals → high oxidative stress + low glutathione → many health problems

What is Glutathione?

If you keep up with the latest nutrition advice, you may have heard of glutathione. Glutathione has become popular in recent years as an important anti-oxidant that is found in some fruits. It is actually one of the body’s most important anti-oxidants, but it does a lot more then just clear out free radicals. In fact, glutathione is involved in a great deal of the body’s metabolism.

So, Just What Is Glutathione?
Glutathione is a small molecule made of three amino acids – the pieces that proteins are built from. The technical term for this kind of molecule is a ‘tri-peptide’.

What Does Glutathione Do?
Glutathione is a very busy molecule. It:

  • Is an antioxidant, protecting the body against free radicals and oxidative stress
  • Helps process medications
  • Processes and protects against carcinogens
  • Clears heavy metals from the body
  • Helps build DNA
  • Helps build proteins

As you can see, glutathione does a lot of important things. Luckily, the body is normally very good at keeping levels of glutathione high enough to take care of everything it needs to. For most people, glutathione will quietly do its job without any problems for their entire lives.

What Happens if the Body Doesn’t Have Enough Glutathione?
When there isn’t enough glutathione, a person has a glutathione deficiency. When a glutathione deficiency develops, then the body isn’t able to protect itself against oxidative stress, process medications, clear heavy metals or protect itself from carcinogens. Some of the health problems that can develop or worsen when this happens include:

  • Alzheimer’s disease
  • Parkinson’s disease
  • liver disease
  • cystic fibrosis
  • sickle cell anemia
  • cancer
  • heart disease
  • stroke
  • diabetes

What Causes Glutathione Deficiency?
Several things can cause a gluthathione deficiency.

Genetic problems in glutathione production: Sometimes something prevents the body from making enough glutathione. There are some rare genetic polymorphisms that directly interfere with the body’s production of glutatione, and some more common polymorphisms on what is called the ‘transulfuration pathway’ and can also lead to a glutathione deficiency. MTHFR is not included in these genetic polymorphisms. MTHFR does not interfere with the production of glutathione.

Poor Nutrition: The body needs animal protein to create glutathione. It cannot manufacture glutathione from plant protein or other sources. However glutathione is already present in a number of fruits. In order to avoid a glutathione deficiency it is important to eat either animal protein or fruits high in glutathione.

The body is good at maintaining healthy levels of glutathione – a few days without fruit or animal protein now and then won’t cause problems, bu one or the other should be a regular part of your diet.

High levels of oxidative stress: Oxidative stress is the only thing researchers have found which is Able to cause a sudden drop in glutathione levels.

MTHFR causes high levels of oxidative stress, which can lead to glutathione deficiency and all the health problems it causes.

More on the connection between MTHFR, oxidative stress, and glutathione.