Dietary Fats Explained!

While skimming through my alumni e-newsletter this weekend, I happened upon an interesting article about dietary fats.  While the main point of the article was to inform generally healthy people about the role of fats in their diet and which fats are healthy, there were some interesting facts in the article that helped me understand my son's MCADD a little bit more.

Some things that I learned:

First, I learned that fats have 4 main roles in our bodies...

1. Energy source and reserve–Fat provides 80-90 percent of the energy requirement at rest. One gram of pure lipid contains about 9 calories of energy, more than twice the energy available from carbohydrate or protein.
2. Protection of vital organs– The body’s internal fat (about 4 percent of the total) protects against trauma to vital organs like the heart, liver, kidneys, spleen, brain, and spinal cord.
3. Thermal insulation–Fat keeps us warm!
4. Vitamin carrier and hunger suppressor–Approximately 20g of daily dietary fat provides a sufficient source and transport medium for the four fat-soluble vitamins: A, D, E, and K. Severely reducing lipid intake depresses the body’s level of these vitamins and may lead to a deficiency.

Although we aren't on a low-fat diet, #4 on the list makes me wonder whether MCADD kids on the low-fat diet may have vitamin deficiencies as a result of not having enough fat to transport vitamins and fully reap their benefits?

Second, I learned that fatty acids have a chain length categorized as short to very long.  This becomes important since the different chain lengths undergo different metabolic fates.  Short-chain and medium-chain fatty acids are quickly available for use as energy. Long-chain fatty acids, in contrast, undergo more complex processes and are deposited as fat in the liver and other body fat cells. Thus, the short- and medium-chain fatty acids often are considered “good” fats since they are easily metabolized and don’t necessarily contribute to fatty livers.

The four different types of fatty acids include: 

1. Short-chain fatty acids = <6 carbons. These are typically found in butter and some tropical fats.
2. Medium-chain fatty acids = 6-12 carbons.  You’ll find these in coconut oil, palm kernel oil, and breast milk.
3. Long-chain fatty acids = 13-21 carbons. These are found in animal, fish, cocoa, seeds, nuts, and vegetable oils. (Chain lengths of 16-18 carbons are most common)
4. Very-long-chain fatty acids = >22 carbons. Examples include omega-3 and omega-6 fatty acids found in fatty fish (omega-3) and some processed vegetable oils

This explains the common information in the MCADD community about avoiding coconut oil and avocado, the only food regularly mentioned to be high in medium chain fats.

Anyway, if you're interested in a deeper dive into fats, I'd encourage you to read the article and, of course, GO BLUE!

MCADD Explained

As promised, here is a little more information about LB's medical condition, MCADD.

MCADD is a fatty acid oxidation disorder found in about 1 in 15,000 babies. Fatty acid oxidation is the process your body uses to turn fats into energy and fatty acid oxidation disorders occur when certain enzymes that break down these fats into energy are either missing or broken. In MCADD, the Medium Chain Acyl-CoA Dehydrogenase enzyme is affected and individuals with MCADD are unable to break down medium chain fats from foods they eat and are also unable to break down medium chain fats stored as body fat. The process looks something like this...

So, if the body can't use the fats, what does it do with them? Basically, it treats them as toxins. Our bodies have substances called carnitines that serve to get rid of waste products.  LB's body is going to end up making a lot of carnitines because not only will they have to get rid of all the "normal" toxins that our bodies need to get rid of, they also have to get rid of the fats that he can't metabolize into energy that his body "thinks" are toxins. The doctors will monitor his carnitine levels periodically and may need to supplement his carnitine levels if he's not making enough.

MCADD can cause bouts of illness called Metabolic Crisis which can include sleepiness, irritability and poor appetite. These can be followed by fever, diarrhea, vomiting and hypoglycemia. Anytime that he is losing nutrients and unable to replenish them, he is in trouble and needs to go to the hospital for a glucose IV, which is, in essence, readily accessible energy for his body to sustain metabolism. If he is not treated quickly for metabolic crisis, he can have breathing problems, seizures and possibly even slip into a coma or die (scary!). Thankfully, metabolic crisis can be avoided simply by not allowing him to fast OR if he is fasting (because he can't keep food down due to illness, etc), we have a can of special formula to feed him. It is called polycose and is basically just pedialyte with HUGE amounts of sugar that his body can immediately use for energy, thus maintaining his metabolism.