No, this is not an ad from Dunkin Donut… of those my fave is still the one they ran some thirty years back, with that funny, slightly overweight franchise owner, doubling as the pastry maker,  slaving away at 2 am….

No, this is December 2014, with DD "owning" the breakfast trade and who knows what else. Making tons of those doughnuts, doughnut holes, croissants, bagels, etc. in the wee hours of the night certainly have paid off!

But look… somebody is upstaging the master pastry maker… sprinkling a liberal amount of CaffeinAll on their chocolate covered doughnuts. About 200-300 mg of it from the looks of it…. 

About 90 percent of Americans consume caffeine daily. More than half of all American adults consume 300 milligrams or more caffeine every day, making it America's most popular drug, according to Live Science. The world’s too, by the way. 

Numerous scientific studies and common experience tells us that for most of us, 200 to 300 milligrams a day are mostly invigorating, not harmful. That’s most of us - how about the ones who exhibit or are in the process of developing sensitivity to caffeine? 

We all know that caffeine can cause restlessness, anxiety, irritability, muscle tremors, sleeplessness, headaches, nausea, diarrhea and abnormal heart rhythms. Unfortunately, these symptoms are not specific only to caffeine but to a host of other conditions and ailments. So it has been very hard till now to connect them. No longer, thanks to rapid advances in genetics.

The metabolism of caffeine in our body

Let us look at a more scientific side of what happens to caffeine inside our body. We will also use this as a means to compare the metabolism of children to adults. 

Caffeine is metabolized in the body by the enzyme Cytochrome P450 1A2 (CYP1A2) in the liver. Every person has two copies of the gene which makes the enzyme CYP1A2 (one copy from each parent). There are 2 variations of this gene which affect how quickly a person metabolizes caffeine. The CYP1A2*1A variety (“allele”) makes an enzyme that metabolizes caffeine very rapidly. However, the CYP1A2*1F allele metabolizes caffeine slowly. The difference between these two alleles is one single nucleotide, an A to C substitution at position 734 of the CYP1A2 gene.

Individuals who have two copies of the fast CYP1A2*1A allele are fast caffeine metabolizers; whereas people who have at least one copy of the slow CYP1A2*1F allele are slow caffeine metabolizers.

As caffeine is metabolized, it is broken down into theophylline, paraxanthine, and theobromine. These travel all over our body and influence many body organs and functions. These also sway moods and prevent the calming effect of dopamine. Theophylline causes smooth muscles to relax and that is why we usually feel like going to the comfort room after ingesting caffeine. On the other hand, theobromine adds to the oxygen and nutrient levels in our body which are used by muscles and the brain.

Stimulation by caffeine increases the rate of metabolism

Although stimulation from caffeine increases the rate of metabolism, it can only achieve this effect when the metabolic support for it is there. The most important element of this support is sufficient blood glucose - blood sugar - in our body. Feeling anxious or shaky is, in most cases, a result of low blood sugar (hypoglycemia).

Add to this that once caffeine is in your system, even more glucose is removed from the bloodstream, since caffeine further stimulates the body’s metabolism. Problems begin when our body cannot provide enough fuel for cells, given the level of stimulation. If too much stimulation occurs, a stress alarm goes off, that mobilizes resources to provide energy to cells. Your body says, “We’ve got lots of stimulation going on here; we need to mobilize resources right now.”

The stress alarm’s basic function is to raise the blood sugar level. This involves the release of glycogen from the liver under the direction of adrenaline and glucagon, and the conversion of body fat first, and protein after that, into glucose using the liver’s help, as it is intimately involved in blood sugar regulation.

Combining low blood sugar (hypoglycemia) and being a slow caffeine metabolizer may give us the explanation as to how people could become sensitive or allergic to caffeine.  

Measuring caffeine sensitivity

Caffeine sensitivity is the inversely proportional with the amount of caffeine that will affect a person. The more caffeine needed to produce an impact on someone, the less sensitive he or she is to caffeine. It is common to say that the smaller or older the person, the less caffeine required to make an effect.

Unfortunately for many of us, sensitivity to caffeine does tend to increase together with increase in age. Children metabolize caffeine quicker than adults. Since children have faster metabolism, they also process the caffeine faster while older people with slower metabolism become somewhat thin-skinned to caffeine and store it for a while.

Other helpful information

Caffeine metabolism DNA testing 

The CaffeineGEN™ test by  Consumer Genetics  is a simple, accurate genetic test that will tell you if you have the fast or slow caffeine metabolizing gene. All you need to do is collect a simple cheek swab sample in the comfort of your home and just days later you will be ready to make positive changes in your life based on your personal genetics.

By knowing your genetic makeup, you can adjust your daily caffeine intake accordingly and manage your overall well-being. 

Genetic links to caffeine sensitivity

Ted Kallmyer of CaffeinInformer.com is one of the foremost experts in all things having to do with caffeine. As he describes in his Caffeine Sensitivity article (see link below):  
"Caffeine is metabolized in the liver using the enzyme CYP1A2. The ability to produce this enzyme is regulated by the CYP1A2 gene. Slight changes in the DNA sequence of this gene determine how efficiently a person can metabolize caffeine and thus eliminate it from the body." 

The Cornelis study

According Cornelis et al. a person who is a fast metabolizer of caffeine can drink up to 6 cups of coffee a day and have no effects. However, bear in mind that the lethal dose is 2 grams of caffeine per day.*

Additionally, the Cornelis et al. study finds that people who have the slow caffeine metabolizing gene can still enjoy caffeinated food and beverages so long as their caffeine consumption doesn’t exceed more than 200 mg per day or more than 2-3 cups of coffee per day.

* Other sources give different values. Some even go up to 14 grams a day! 

References

http://www.caffeineinformer.com/caffeine-sensitivity

http://www.livescience.com/6252-caffeine-sensitivity-increase-age.html - Fred Cicetti

http://www.functionalps.com/blog/2014/06/04/coffee-done-right-tips-to-help-avoid-coffee-intolerance/ - Team FPS

http://www.consumergenetics.com/DNA-Tests/Caffeine-Metabolism-Test.php

Cornelis MC, El-Sohemy A, Kabagambe EK, and Campos H. “Coffee, CYP1A2 genotype, and risk of myocardial infarction.” JAMA 2006, 295:1135-1141

Researchers at the Harvard School of Public Health discovered six “coffee genes” after reviewing 28 previous studies on the genetic makeup of more than 120,000 coffee drinkers. They compared each person’s genetics to how much coffee they said they regularly drank each day.

“Out of 2.5 million variants in the genome, we found a handful that were strongly linked to coffee consumption. Two other genes appear linked to the kick that a person receives from caffeine. These genes are tied to the brain’s pleasure centers and likely influence the amount of stimulation or enjoyment that caffeine provides,” Marilyn Cornelis says in the article.

Two of the genes are related to the way a person’s body metabolizes caffeine, the study reports. This indicates that the genes might affect the brain process that senses blood glucose levels, which may, in turn, influence a person’s response to caffeine.

The final two genes “were really unexpected,” Cornelis says. Those genes previously have been linked to metabolism of fats and sugars, and they had not been suspected as influencing the body’s response to coffee.

“Individuals who consume larger quantities of coffee may metabolize caffeine more quickly than others, and this could be due to their genetic makeup,” according to Poole, another researcher who participated in the study. He warns that while these specific genes respond to caffeine, there likely are other factors that influence a person’s love of coffee.

“It would not be correct to conclude that coffee consumption is driven solely by genetic responses to caffeine. There are many bioactive compounds in coffee that could determine coffee consumption,” she says. 

The article was published in the Molecular Psychiatry journal, 10/7/2014.

Coffee may be just a beverage for most people. 

But for Chef Paul Neukirch from Malaysia, it's an ingredient to be used in daily cooking. It "adds a certain zing" he says. In fact, he says many Malaysians even have a shot of espresso and hit the sack at night. 

Malaysian coffee is an acquired taste — it's thick, strong, and bitter. The distinctive burnt flavor, chefs believe, comes from the butter and sugar that the beans are roasted in. Cooking with this coffee was a challenge for Neukirch. But after 10 days of trial and error, he created 4 delicious dishes you too can enjoy!

Espresso Risotto

Ingredients: 

5 cups chicken broth.
1 and ½ cups risotto rice.
¼ cup espresso.
¼ cup white wine.
¼ cup grated parmesan.
1 small onion cubed fine.
2 tablespoons unsalted butter.
2 tablespoons olive oil.
8 espresso beans.
2 capers.
Salt and pepper to taste.

Instructions: 

Chop the capers fine. Reduce espresso to 2 spoons. Heat up stock. Heat up olive oil and simmer onions until they are translucent. 

Add the rice and espresso beans. Add stock and boil rice up to 20 minutes. Discard espresso beans. 

Stir in butter and stock (if needed). Season with salt and pepper. Garnish with capers and reduced espresso and add cheese.

TIP: Use hot coffee, otherwise the risotto and coffee separate. When the coffee is hot, it blends into the risotto.

Spicy Lamb Stew

Ingredients: 

1 cup coffee.
½ cup chicken or vegetable stock
9 oz boneless lamb leg or shoulder
1 red onion, medium
1 red chili
1 green chili
5 pieces garlic
2 tablespoons brown sugar
1 tablespoon bbq sauce
1 tablespoon olive oil
1 lemon grass
1 ginger fresh   
Chili flakes to taste

Instructions: 

Blend chili, onion, garlic, lemongrass, ginger and chili flakes.
Heat up oil and whisk brown sugar in it until golden brown. 
Add spice mix and stir well for 2 minutes. 
Add lamb meat and stir well for 2 minutes. 
Add chicken or vegetable stock and simmer on low heat for 2 hrs 30 mins. 
Add coffee. Reduce until sauce thickens. Season with salt and pepper.

Summer Greens with Coffee Braised Duck Breast and Orange

Ingredients: 

1 duck breast
1 cup coffee
½ cup orange juice  
½ cup olive oil
¼ cup minced fresh salad greens, your choice
2 segments of orange
2 tablespoons minced onion sprouts
2 tablespoons pine nuts
1 tablespoon orange zest
Salt and pepper to taste

Instructions: 

Bring coffee to a boil until it reduces by half. 
Add duck breast and heat in saucepan until the coffee is reduced totally. 
Let duck rest for 15 minutes and grill to perfection. 
Roast pine nuts until golden brown. 
Mix orange juice, olive oil, salt, pepper and orange zest for dressing. 
Mix salad with dressing until all covered. 
Assemble salad and decorate with orange segments, sprouts, and pine nuts. 
Add warm slices of braised duck breast.

Robusta Creme Brule

Ingredients: 

1 cup strong espresso
1 cup heavy cream
4 egg yolks
3 tablespoons sugar
1 dash cinnamon
½ vanilla pod

¼ cup sugar, caramelized separately.

Instructions:  

Pre-heat oven to 315 F / 150 C.
Mix egg yolks and sugar until creamy white. 
Add vanilla pod to egg and sugar blend. Mix in cream and cinnamon. 
Bake in a water bath for 25 minutes. 
Chill and garnish with caramelized sugar.