Snacking Sensations

Squirrels know where it's at, as usual, and apparently nuts are a very good snack, especially if you want to lower your cholesterol levels! This is because they have a relatively high levels of Mono-unsaturated fats and Poly-unsaturated fats. Recent research has shown that while Trans-fats still greatly increase heart disease risk, and Poly and Mono-unsaturated fats still decrease heart disease risk, Saturated fat is actually a fairly neutral substance compared to carbohydrates. So while nuts tend to have some Saturated fat, the Mono and Poly-unsaturated fats make them a beneficial food. Especially good for you is Poly-unsaturated fats.

Substituting 2% of your daily calories (that's only like 25 calories people) from Trans fat to Poly-unsaturated fat reduces your risk of coronary heart disease by more than HALF.

Don't eat Trans fat! Don't do it!

A scary problem with avoiding Trans fat is that a food with up to a half a gram of trans fat per serving is allowed to be labeled as containing zero grams trans fat, or as trans fat free. Since the recommended daily limit of trans fat is only 2 grams, you can get over this limit pretty easily by eating only "trans fat free" foods. Also remember that this is per serving; a serving of Oreos is 2 cookies, and I know you haven't ever had just two Oreos.

Trans fat is not found in nature, so only processed foods will contain them. Food manufacturers started using them because they turn liquid fats, which are more perishable and messy, into handy solid fats (think margarine). Things to avoid:

Stick Margarine, and any tub Margarine that doesn't say it is trans-fat free

Donuts

Fast Food

That fake cream stuff in twinkies and the like

(Have you ever heard of the cardiologist's diet? If it tastes good, spit it out.)

All right, back to the nuts. The BEST nuts:

1. Hazelnuts (these are like superfood)

2. Walnuts (has the most poly-unsaturated)

3. Pecans

4. Almonds

The not-so-great nuts (sorry dad):

1. Brazil Nuts

2. Cashews

3. Peanuts

So eat your walnuts and hazelnuts! (Trader Joe's, and probably other stores, make delicious spicy or caramelized walnut/pecan snacks which make an excellent substitute for mixed nuts. You should all try.)

When Your Body has Poor Financial Judgement

McArdle's Syndrome

McArdle's Syndrome is a glycogen storage disease (Type V, for those counting), so it's a problem with our savings account. These patients are allergic to exercise which makes this the dream disease of nerds everywhere (McArdle even sounds like a good nerd name, doesn't it?). People with McArdle's syndrome are lacking the muscle form of glycogen phosphorylase, so they are unable to convert stored glycogen (savings) back into glucose (checking) to use in glycolysis (ATM). So when they begin exercising, their muscles use up the available glucose, and then are left with no fuel source, which understandably causes some problems (in this case muscle cramps). Luckily for the lives of those with McArdle's, the liver version of phosphorylase is still active, so these patients can still convert glycogen stored in the liver to glucose, and get the necessary energy to all cells, but in strenuous exercise the liver just can't keep up with the muscle.

Those who can't convert the liver glycogen into free glucose get the much worse.....

von Gierke's Disease

Patients with von Gierke's are missing glucose 6-phosphatase, which is a key enzyme in turning liver based glycogen into free glucose. So these patients can accumulate money in their savings account, but never take it back out again- trust fund! Kinda. This is a major problem, because once the free glucose from meal has been used up, the patient's body has no energy source to turn to. This can cause severe hypoglycemia (low blood sugar) with even short lengths of fasting, such as the time between normal meals. Patients present in infancy with massive enlargement of the liver (because of glycogen buildup), hypoglycemia, acidosis (low blood pH) and growth failure. The disease is relatively easy to control in adults by frequent ingestion of corn starch which is slowly digested to provide a continuous source of glucose. However infants usually require a 24-7 nasogastric feeding tube until they are old enough to be persuaded to eat cornstarch all day.

But of course glycogen metabolism isn't the only process that can have problems....

Beriberi

I love tropical diseases. They have such fantastic names, which means they are about the only diseases I remember over long periods of time. Beriberi is a severe thiamine (vitamin B1) deficiency. It is a tropical disease because thiamine isn't that rare of a vitamin, so severe deficiency usually only occurs in populations that rely entirely on polished rice for food. Thiamine deficiency in the developed world occurs in alcoholics who are mostly relying on alcohol for their caloric intake. It is given the much more dull name of Wernicke-Korsakoff syndrome, or as I like to call it, AlkyBeriberi.

Thiamine is necessary for the TCA cycle, which we haven't talked about yet. The TCA cycle is like glycolysis, in that it produces ATP (cash). It actually takes glycolysis byproducts, and further extracts ATP from them, but requires other inputs as well, such as oxygen. The TCA cycle, though, is much more efficient than glycolysis, and actually provides the majority of our ATP.

So people with Beriberi have a severe lack of energy supply in their cells, which means that their bodies' systems begin to gradually shut down. The nervous system is the first affected because the brain is much more dependent on glycolysis and the TCA cycle for energy. Other tissues are also capable of using fats and proteins through other pathways. So patients exhibit mental confusion, unsteady gait/lack of motor control, vomiting, and coma. Those with Wernicke-Korsakoff also sometimes exhibit a strange type of congestive heart failure that is characterized by high cardiac output.

Also interestingly, Arsenic and Mercury poisoning disables the same enzyme that is disabled in Beriberi, leading to similar mental/neurological problems. This is the origin of the phrase "Mad as a Hatter", because hat makers used mercury nitrate in their hat making processes, frequently succumbing to mercury poisoning.

Glucose, my Cruel Mistress.

Or, what happens when there is too much biochemistry.

So, we eat. We eat to give our body energy. You would think that something this straightforward would be simple, but no. It's not, in a big way. And, it's only like 10 freaking percent of the material on the next biochem quiz, but I'm not bitter. And it gives me a lovely ridiculous analogy!

Specifically, we eat carbohydrates, which are turned into glucose in our stomachs, and then absorbed into our blood and carried everywhere, because our cells transform glucose into ATP, which is the cell's unit of energy, via glycolysis.

ENTER THE ANALOGY (stay with me here)

So glucose = my mother's electronic transfer of money into my checking account. It's great, because I now have more money, but I can't actually spend it at the local farm. Because the farm doesn't take checks or credit cards, and neither do your cells. You have to turn your electronic money into cash (or ATP) because this is what the farmer (your cells) uses to pay the rent. You do this via an ATM machine, or glycolysis.

So whenever your cells need a little spending money/energy (ATP), they go to the ATM (use glycolysis) to get some from the checking account (glucose). But cells are just like me- I get one big transfer each month, the cells get a pile of glucose each meal. You don't want all that extra glucose/money just floating around- a thief (the kidney) might steal your debit card, and spend (pee) all your money (glucose). And then you would be broke (dead) for the rest of the month (forever).

So along comes insulin! Insulin is released when there is lots of glucose in the blood. It causes the uptake of glucose into the liver and muscle via glycogen synthesis, where it is stored in a more stable form, glycogen. In our fancy analogy, the money in the checking account (glucose) is transferred (by glycogen synthase) to the savings account (glycogen in liver and muscle) in response to insulin (your good sense).

So now your body is trucking along after its meal, and it uses up all its free glucose. Aka, it's the middle of the month, and I've eaten out one too many times. Now I need to buy groceries from the farmer, and your cells still want to keep living, like the pesky things they are. But just like in my real life, you can't withdraw cash from your savings account. (Electronic transfers only. ING Orange. Over 1% interest. Check it out people.) You have to first transfer it to your checking account.

So- You need more ATP (money), and for that you need Glucose (money in your checking account) but you've used it all up. Glucagon signals a need for more glucose, so you go to your liver and muscle for glycogen (savings account). You convert your glycogen into glucose via gluconeogenesis (electronic transfer from savings to checkings), and then convert the glucose to ATP via glycolysis (get money from checking via ATM).

YAY!

Of course it is too late for me to get to the interesting disease parts, but that will come tomorrow.

The Twisted Ways My Brain Works

Here is the TCA cycle (important in cellular respiration aka life)

Citrate -> Isocitrate -> alpha Ketoglutarate -> Succinyl coA -> Succinate -> Fumarate -> Malate -> Oxaloacetate

Here is my "mnemonic"

Lemon -> Kind of Lemon -> tricky one -> Even though your friends suck on cigarettes, you shouldn't suck on cigarettes, because if you smoke, it is bad for you, and the have to give you oxygen.

I wonder at my brain sometimes.