Irony of iron-rich foods

If you work night shifts, then you might want to think twice about tucking into a juicy steak for dinner. If you're a vegetarian or the health conscious type who would opt for brown rice and greens instead, then too, you might want to rethink your dinner menu. The reason being, eating iron-rich foods at night can disrupt your liver's circadian clock. We spoke to experts on to shed light on the matter and suggest food alternatives.

The study
This new new research shows eating foods high in iron disrupts the body clock among individuals clocking in to the graveyard shift. Sleeping, waking and digestion is regulated by the body's circadian clocks over a 24-hour-period. And these cycles activate processes in all the cells in the body, affecting the release of hormones controlling metabolism and other functions. The brain acts like the body's main circadian clock, ensuring all the other body clocks are in sync. Since the body's natural circadian clock is dictated by light, telling us to wake up in the morning and sleep when it's dark, working in night shifts disrupt this cycle. Therefore, it is also said that individuals working during the nocturnal hours have a higher risk of type 2 obesity, diabetes and cancer.

Some researchers have now discovered that having iron-rich foods disrupts the circadian clock in the liver (among night shift workers) which helps maintain constant blood sugar levels. Normally when a person is asleep, the liver's circadian clock maintains a constant blood sugar level and the level then spikes just before they wake up.

Now comes the iron(ical) part. Iron acts like a wheel in the liver's circadian clock, by prompting the liver to go into overdrive, strictly controlling blood sugar levels, thereby preventing their spike. Now this would be healthy when it occurs in the liver's natural clock cycle. However, if this occurs at a time that is not in sync, like during a night shift, it could result in abnormal blood sugar levels. Speaking of night shift workers, their liver's circadian clock is already out of sync with the brain's circadian clock, and eating iron could aggravate this lack of sync. This in turn could lead to diseases like obesity, diabetes, and stroke, opine the researchers.

The study was conducted by experiments on mice by feeding them iron as part of their natural eating cycle. The researchers found that iron in the diet increases the concentration of heme, an oxygen carrying compound found in haemoglobin, in cells. When heme binds to a circadian protein, the protein's activity increases. This causes the liver to increase its activity of controlling blood sugar levels. Therefore, eating iron-rich foods caused the liver to increase its activity in regulating blood sugar. This interferes with the normal fluctuations associated with a healthy metabolic system and leads to diseases like obesity, diabetes, stroke and cancer.

Lead author of the study, Judith Simcox said, "Iron is like the dial that sets the timing of the clock. Discovering a factor, such as iron, that sets the circadian rhythm of the liver may have broad implications for people who do shift work." Co-author of the study professor Donald McClain added, "When a shift worker eats foods high in iron at night it could exacerbate the lack of synchronsation between the clock in the liver and the main one in the brain. By tending to flatten the circadian variation of metabolism, high iron in tissues may also interfere with the normal day to night fluctuations associated with a healthy metabolic system." The study appeared online in the journal Diabetes.

Expert speak
Consultant diabetologist, Diabetes Relief, Dr Deepak Patil disagrees with the study saying, "I don't agree with these findings as I think the aforementioned study on mice is inadequate to draw any such conclusion of avoidance of iron rich food by shift worker as consumed dietary iron is very small in quantity, which is unable to alter human liver function." He further adds that he has seen patients who work in shifts and are coming with deranged blood sugar profile but not because of iron rich food at dinner or supper but because of of disturbed circadian clock due to irregular eating and sleeping pattern.

Nutritionist, fitness consultant and founder of Selfcare, Suman Agarwal says, "I agree with the study that having high protein meals with steak or other meats can disrupt the body clock and cause ailments like diabetes, metabolic syndrome, cancer etc. It's not only the night shift workers who are in question here but a lot many young adults and adults lead a life where the are eating after 12 and face similar health issues."

Disturbed circadian clock puts liver under stress
The liver is a master laboratory of body and reflects promptly when circadian cycle is disturbed especially in shift workers and exposes them to the great risk for diabetes, obesity and cardiovascular complications. It affects the liver to great extent. Disturbed circadian clock put liver under stress which results in to derangement of blood sugar profile and leads to early exposure to Type 2 diabetes mellitus, opines Dr Patil.

Meal alternatives
In her practice, Agarwal has seen pilots facing this problem and here's what she recommends:
Dinner time remains at around 8 to 9 pm, which is a combination of carbs, proteins and fibre. It could be rice or chapattis with chicken or dal or fish, and vegetables as source of fibre. Through the night we recommend high-carb, low-protein and low-fat foods such as fruits, juices, jam sandwich, puffed rice, yoghurt, milk and cereal etc. Then between 5 am, we advise a meal that is similar to lunch, but a light one. For example, an egg sandwich or chicken sandwich or curd and parathas, etc.

Iron-rich foods
Red meat
Dried fruit, such as dried apricots, prunes and raisins
Brown rice
Dark green leafy vegetables