Caffeine has a mild diuretic effect, which leads to an increase in urination. As a result, water-soluble vitamins, such as B-vitamins and vitamin C can be depleted due to fluid loss. Research also demonstrated that the higher the level of caffeine, the more it interfered with vitamin D absorption.
Caffeine also causes the body to dump other key nutrients like calcium, magnesium, potassium and iron. Have I made my case yet? Coffee can affect your mood. Instead of boosting your mood, caffeine actually produces stress hormones, which can trigger anxiety, irritability and insomnia.
Coffee also seems to impact on the metabolism of some B vitamins like thiamine. Vitamin B12, though, looks like being a possible exception – indeed, caffeine's stimulation of stomach acid production may actually assist, instead of compromise, your body's B12 absorption.
Caffeine and nutrient absorption.
Any food or drink that contains caffeine - including coffee, tea, chocolate and some fizzy drinks - may inhibit the bioavailability of vitamins and minerals in the bloodstream and prevent the nutrients from doing their job.
Coffee does not directly affect magnesium in your body. But it halts the further absorption of magnesium gradually in your intestines. The more coffee you consume, the less your magnesium absorption rate gets. But a heavy dose of coffee can lead to magnesium depletion.
For every cup of coffee, you consume, you lose an estimated 10 milligrams of calcium. While coffee does not directly affect magnesium levels already present in your body, it does, however, affect your body's absorption of magnesium.
The tannins and caffeine can interfere with the absorption of many vitamins and minerals, especially iron. Caffeine also increases urination, which can decrease the concentration of water-soluble vitamins (B-complex and C). So, wait an hour after your morning brew to take supplements.
Gibson noted that drinking too many caffeinated beverages, “affects your immune system.” He elaborated on the effect, saying, “Chronic elevations of cortisol can alter the immune system responses.” Like dopamine, cortisol affects a person's mood and body, but this hormone causes stress.
Caffeine has a mild diuretic effect, which leads to an increase in urination. As a result, water-soluble vitamins, such as B-vitamins and vitamin C can be depleted due to fluid loss. Research also demonstrated that the higher the level of caffeine, the more it interfered with vitamin D absorption.
Caffeine may reduce the absorption of manganese, zinc and copper. It also increases the excretion of the minerals magnesium, potassium, sodium and phosphate. There is also evidence that caffeine interferes with the action of vitamin A.
Conditions affecting the stomach
Some stomach conditions or stomach operations can prevent the absorption of enough vitamin B12. For example, a gastrectomy, a surgical procedure where part of your stomach is removed, increases your risk of developing a vitamin B12 deficiency.
Caffeine is a stimulant, which means it increases activity in your brain and nervous system. It also increases the circulation of chemicals such as cortisol and adrenaline in the body. In small doses, caffeine can make you feel refreshed and focused.
For instance, it is empirically known that ingestion of caffeine (especially in large amounts) can induce hypokalaemia. Although the detailed mechanism has not been clarified yet, losing potassium (K+) via the urine stream due to the diuretic action of caffeine is proposed as one of the possibilities.
Some studies link caffeine consumption with negative effects on calcium metabolism, possibly related to caffeine increasing loss of calcium in the urine, and decreasing calcium absorption in the body. Over time, having less calcium available could cause bone loss.
Caffeine can interfere with the absorption of certain minerals, including magnesium, calcium, and iron, but the loss is minimal.
"In terms of inhibiting iron absorption, the most common ones that I see are coffee and tea being consumed at the same time as iron-rich meals," he says. "The tannins and the polyphenols in these drinks—as good as they are for you—will inhibit iron absorption."
Vitamins and minerals
Let's start with magnesium. A cup of coffee contains about 7 mg, which is a drop in the daily-requirement bucket (420 mg for men, 320 mg for women). But because we don't eat enough fruit, vegetables, and whole grains, the average American's intake falls about 100 mg short of the daily goal.
Additionally, certain food products such as tea, coffee, raw fish, and shellfish contain thiaminases - enzymes that destroy thiamine.
How? Caffeine suppresses collagen production by preventing cell growth and interfering with the development of cartilage. In turn, this affects the ability to make new collagen and the genes involved in maturing cartilage cells. One study found that caffeine reduces collagen synthesis in human skin.
Caffeine leaches calcium from bones, sapping their strength. "You lose about 6 milligrams of calcium for every 100 milligrams of caffeine ingested," Massey says. That's not as much of a loss as salt, but it's worrisome, nonetheless.
High levels of caffeine intake may increase your risk of osteoporosis. About 400 mg a day or less probably won't cause bone loss (or other health problems), while 800 mg or more is considered the threshold for osteoporosis risk.
Common substances — such as sugar and caffeine — deplete the body's magnesium levels.