Why apples are better at keeping you awake than coffee

For all of my dear coffee-drinking friends (you know who you are :)

Coffee is a drink that contains significant amounts of caffeine. Apples are a fruit that are primarily sugars and starch. With just this information, it seems rather contradictory that sugar and starch can overcome the awakening power of caffeine, which many college students (including myself) have used to get through finals weeks. Yet, diving into the chemistry, not only are apples a healthier alternative, but they are a chemically and biologically superior option to caffeine.

Caffeine

To use a formal definition, caffeine is a “naturally occurring central nervous system (CNS) stimulant of the methylxanthine class”. To break this down, the central nervous system includes the brain and spinal cord. Defining the methylxanthine class requires following a chain of a few other definitions, as follows (not essential for the understanding of the mechanisms, more so for personal interest):

1) They are a group of phosphodiesterase inhibitors.

2) Phosphodiesterase inhibitors are drugs (chemicals) that affect phosphodiesterase enzymes, in one of five ways.

3) Phosphodiesterase enzymes regulate intracellular concentrations of cAMP and cGMP.

4) cAMP is an intracellular messenger that is key in many signalling pathways. cGMP is also an intracellular messenger, with a focus on regulating downstream effects.

The mechanisms

Caffeine, in a sentence, replaces the physical place of adenosine thus denying its ability to induce tiredness. Adenosine is one of the building blocks of RNA, and you are most likely to have heard of it in the context of ATP/ADP (adenosine tri/biphosphate). When adenosine binds to receptors in the brain, it sets off the pathways to suppress neural activity in a way that increases tiredness. The basal forebrain naturally releases adenosine as energy is used, thus increasing the need for sleep. 

Caffeine acts as an adenosine receptor antagonist. This means that it is able to bind to the same receptors that otherwise would have accepted adenosine. If less adenosine molecules can bind to their receptors, it cannot set off the signals that would cause tiredness to their natural magnitude.  

As an additional feature, caffeine causes neural excitation. The pituitary gland recognizes this, and communicates to the adrenal gland via hormones to produce more adrenaline - keeping you awake. Adrenaline contracts your blood vessels, relaxes your airways to give your muscles more oxygen, increases your heart rate, and generally makes you more alert. The effects of an adrenaline rush tend to last an hour after.

As a quick sidenote, caffeine also increases production of dopamine (you might recognize it as the pleasure chemical), which causes addiction. Caffeine withdrawal symptoms are very real.

Caffeine is not very effective at giving you more energy. It simply lessens the amount of tiredness you feel, gives you an adrenaline rush, and gives you a rush of pleasure through the production of dopamine. Yet, late night study sessions are more than about not falling asleep. They’re about keeping your brain at a good operating capacity, in a state of focus, with sufficient energy - all results that apples can provide for you.

Apples

Apples have two main ‘ingredients’ that contribute to their ability to lead to increased alertness: 1) natural sugars; 2) fiber.

1) Apples contain high concentrations of fructose, which is quickly broken down and absorbed into your bloodstream. This leads to a rapid increase in blood sugar levels, which increases energy and alertness.

2) Apples won’t cause the same drop in energy that caffeine does after the boost - apples are a good source of pectin, which is a dietary fiber. It’s a polysaccaride (a long chain of sugars we can’t digest), and it expands into a gel-like substance in the presence of water. This makes the sugar also in the digestive system break down slower, and be absorbed more slowly.

Apples are excellent. If their ability to keep you energized and focused while you study is insufficient, consider their health benefits.

There’s this literature study that goes over the benefits of apples linked here. The main takeaways: apples have many phytochemicals that are strong antioxidants, which is excellent for long-term health. Some examples include:

• Quercetin: It has “protective abilities against tissue injury induced by various drug toxicities”.

• Catechin: It protects cells from damage from free radicals (explained in the earlier butterfly posts!).

• Phloridzin: It inhibits the sodium-glucose cotransporter (SGLT1) in the intestine, which reduces glucose absorption and improves regulation of blood sugar.

• Chlorogenic acid: It improves blood sugar control and cardiovascular health.

Conclusion

In my personal experience, caffeine works great at keeping me awake. I take great care in drinking caffeinated drinks such as black tea and coffee only a small handful of times per year in order to prevent any resistance to its effects. (Yes, I am aware that this is too cautious, but prefer to err on the side of error). However, it’s just satisfying to bite into big slices of green apple and snack on them while I workon problem sets!