Did you know? Accompanying your meal or breakfast with a coffee is very pleasant (and common). However, this can reduce the absorption of essential minerals or disrupt digestion. Here’s how to avoid these interactions and get the most out of coffee, like its nutrients.
Coffee, a pleasure that influences the absorption of certain nutrients
Appreciated for its stimulating effects, we often forget that coffee also affects our digestion and the absorption of certain nutrients. Caffeine, first of all, accelerates transit, stimulates the kidneys and modifies the way our body assimilates several minerals. Added to this are the polyphenols and tannins of coffee. They are capable of binding to certain micronutrients and reducing their bioavailability.
“This is not a health risk“, immediately reassures nutritionist Orlane Fagnoni, “but rather a question of timing. Taken at the wrong time, coffee can make certain foods or supplements less effective. However, simple adjustments can prevent this phenomenon.“.
Vegetable iron, first affected by coffee tannins
If there is one nutrient that particularly suffers from the presence of coffee, it is iron — especially iron of plant origin, called non-heme iron. Present in pulses, green vegetables, whole grains and even tofu, this type of iron is much more sensitive to coffee tannins than animal iron. According to Orlane Fagnoni, “The bioavailability of iron can decrease by up to 40% when you drink coffee within an hour after an iron-rich meal.”
This is why it is advisable to space coffee from foods such as lentils, chickpeas, beans (red, white), spinach, chard, broccoli, quinoa, oatmeal, wholemeal bread, tofu or tempeh. Iron supplements are also affected.
“Ideally, we allow between an hour and an hour and a half between an iron-rich meal and a cup of coffee. Conversely, consuming vitamin C within the same meal — for example by eating an orange, kiwi or raw pepper — improves iron absorption. For this type of meal, it is therefore better to end with fruit rather than coffee.”
Calcium, slightly hindered by caffeine
Another sensitive nutrient: calcium. Caffeine slightly reduces absorption and increases urinary excretion. “Even if the effect remains more moderate than for iron, it can become significant in people who pay attention to their bone health, particularly in perimenopause, menopause or postpartum”warns the expert.
It therefore becomes wise to postpone coffee consumption when consuming milk, yogurt, cheese, calcium-enriched vegetable drinks, sardines, almonds or broccoli. Supplements combining calcium and vitamin D, common in winter, are also sensitive to this interaction.
“One hour apart is generally enough to avoid this phenomenon” advises the expert.
Magnesium and zinc: an impact on supplements and foods rich in minerals
Coffee may also increase the elimination of magnesium by the kidneys and interfere with the absorption of zinc. These two minerals, often taken in the form of supplements, therefore see their effectiveness diminish if coffee is consumed too close to their ingestion. Foods rich in these nutrients — such as
almonds, Brazil nuts, seeds, cocoa, dark chocolate or certain enriched mineral waters — are also affected.
To optimize the assimilation of food supplements, Orlane Fagnoni recommends a simple routine: take them as soon as you wake up with a glass of water, then wait thirty to forty-five minutes before drinking the first coffee of the day. “This small window allows the body to assimilate minerals without interference.”
Citrus fruits and acidic foods: a combination that can worsen digestive discomfort
For people with a sensitive stomach or prone to reflux, the combination of coffee + acidic foods can be uncomfortable. “Coffee, already acidifying, can accentuate burns, acid reflux or bloating when consumed with citrus fruits, tomatoes, salad dressings, fruit juices or spicy dishes“lists the nutritionist.
In these situations, it is best to avoid coffee on an empty stomach and consume it away from meals containing naturally irritating foods. “People suffering from gastritis, gastroesophageal reflux or irritable bowel syndrome have every interest in adopting this reflex.
Fast sugars: a blood sugar spike amplified by coffee
Finally, coffee is often associated with sweet products:
pastries, sweet cereals, white bread slices with jame, biscuits… However, this duo creates an unfavorable combination. Caffeine stimulates the secretion of cortisol, which reinforces the blood sugar spike induced by fast sugars.
Consequence: a very brief boost in energy, followed by a sudden drop in blood sugar levels and a bout of fatigue.
“It can even encourage snacking a few hours later.”
To avoid this glycemic roller coaster, Orlane Fagnoni advises favoring protein and fiber intake at breakfast. Then shift the coffee a little later in the morning. This helps stabilize blood sugar levels and better benefit from the stimulating effects of coffee.
Foods that go very well with coffee
Finally, let’s end with the many options that fortunately remain compatible with a cup of coffee, without negative interactions: “eggs, peanut butter, peanuts, low-acid fruits…” according to our expert.
In conclusion: a coffee is always welcome, provided you position it well.
How to organize your day around coffee?
The ideal organization depends on your habits and your needs, but a few simple guidelines allow you to optimize the assimilation of nutrients without thinking too much about it.
- “After a meal rich in minerals such as iron or calcium, it is wise to wait an hour to an hour and a half before drinking coffee.”
- For food supplements, particularly those taken in winter (iron, zinc, magnesium, vitamin D), it is preferable to respect an interval of thirty to sixty minutes. “In the morning, if you are deficient in iron or calcium, start with your foods or supplements then reserve the coffee for later”;
- People with a fragile stomach, for their part, should avoid coffee on an empty stomach and be careful not to combine it with highly acidic foods.
In short, for the Fagnoni expert, the most appropriate times to enjoy your coffee are often mid-morning or mid-afternoon. Or away from the meals richest in minerals. A simple way to enjoy all the benefits of coffee… without compromising your diet.