Health for life

Maternal nutrition is important to a developing embryo and to the health of the child later in life. Supplementing the diet with specific vitamins is known to increase health of the fetus for example folic acid (vitamin B9) reduces the risk of spina bifida. However not everything an adult might consume is beneficial to a developing baby. New research published in BioMed Centrals open access journal BMC Medicine shows that caffeine is linked to low birth weight babies and that caffeine from coffee in linked to increasing length of pregnancy.

Along with nutrients and oxygen, caffeine freely passes the placental barrier, but the developing embryo does not express the enzymes required to inactivate it efficiently. The WHO currently suggests a limit of 300mg per day during pregnancy but some countries recommend a limit of 200mg, which can be less than a single cup of coffee from some high street cafes.

To investigate the impact of maternal caffeine during pregnancy on babies, a research team from the Norwegian Institute for Public Health used information about mothers diet and birth details collected over ten years. After excluding women with medical and pregnancy-related conditions almost 60,000 pregnancies were included in the study. All sources of caffeine were monitored in the study: coffee, tea, fizzy drinks, as well as food including cocoa-containing cakes and deserts and chocolate.

Explaining their results, Dr Verena Sengpiel, from Sahlgrenska University Hospital, Sweden, who led the project said, "Although caffeine consumption is strongly correlated with smoking which is known to increase the risk for both preterm delivery and the baby being small for gestational age at birth (SGA). In this study we found no association between either total caffeine or coffee caffeine and preterm delivery but we did find an association between caffeine and SGA. This association remained even when we looked only at non-smoking mothers which implies that the caffeine itself is also having an effect on birth weight."

In fact they found that caffeine from all sources reduced birth weight. For a child of expected average weight (3.6kg) this equates to 21-28g lost per 100mg caffeine per day. But it was not just caffeine, but the source of caffeine, which affected pregnancy outcomes. Caffeine from all sources increased the length of the pregnancy by 5hr per 100mg caffeine per day, but caffeine intake from coffee was associated with an even longer gestational length -- 8hr extra for every 100mg caffeine per day.

This association means that it is not just the caffeine in coffee which increases gestational length but either there must be a substance in coffee which is responsible for the extra time or there is a behaviour associated with coffee drinking not present in women who drink only tea (for example). SGA babies are at higher risk of both short term and lifelong health problems and it seems from these results that since even 200-300mg caffeine per day can increase the risk of SGA by almost a third these recommendations need to be re-evaluated.

People with type 1 diabetes are at risk for low blood glucose (BG) during and after exercise.

An abstract¹ presented at this years 70th Scientific Sessions of the ADA found that supplementing with caffeine prior to exercise prevented low BG:

"Caffeine ingestion prior to exercise reduces the fall in BG, and the requirement for glucose ingestion during exercise in type 1 diabetes mellitus (T1DM), but does not alter respiratory exchange ratio (RER) and thus fuel oxidation. This implies that caffeine augments endogenous glucose production with exercise. Caffeine may be an additional tool to reduce hypoglycaemia during exercise in T1DM."

It was a small study, only 5 participants. They took a 5mg/kg dose of caffeine. That works out to 340mg of caffeine for a 150 lb woman, or 454mg caffeine for a 200 lb man. An 8 ounce cup of regular brewed coffee has about 100mg caffeine.
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¹ Caffeine Supplementation Reduces Exercise Induced Decline in Blood Glucose and Subsequent Hypoglycaemia in Adults with Type 1 Diabetes (T1DM) Treated with Multiple Daily Insulin Injection (MDI), Abstract ADA 70th Scientific Sessions, June 2010

Recent studies have linked caffeine consumption to a reduced risk of Alzheimers disease, and a new University of Illinois study may be able to explain how this happens.

"We have discovered a novel signal that activates the brain-based inflammation associated with neurodegenerative diseases, and caffeine appears to block its activity. This discovery may eventually lead to drugs that could reverse or inhibit mild cognitive impairment," said Gregory Freund, a professor in the U of Is College of Medicine and a member of the U of Is Division of Nutritional Sciences.

Freunds team examined the effects of caffeine on memory formation in two groups of mice—one group given caffeine, the other receiving none. The two groups were then exposed to hypoxia, simulating what happens in the brain during an interruption of breathing or blood flow, and then allowed to recover.

The caffeine-treated mice recovered their ability to form a new memory 33 percent faster than the non-caffeine-treated mice. In fact, caffeine had the same anti-inflammatory effect as blocking IL-1 signaling. IL-1 is a critical player in the inflammation associated with many neurodegenerative diseases, he said.

"Its not surprising that the insult to the brain that the mice experienced would cause learning memory to be impaired. But how does that occur?" he wondered.

The scientists noted that the hypoxic episode triggered the release of adenosine by brain cells.

"Your cells are little powerhouses, and they run on a fuel called ATP thats made up of molecules of adenosine. When theres damage to a cell, adenosine is released," he said.

Just as gasoline leaking out of a tank poses a danger to everything around it, adenosine leaking out of a cell poses a danger to its environment, he noted.

The extracellular adenosine activates the enzyme caspase-1, which triggers production of the cytokine IL-1β, a critical player in inflammation, he said.

"But caffeine blocks all the activity of adenosine and inhibits caspase-1 and the inflammation that comes with it, limiting damage to the brain and protecting it from further injury," he added.

Caffeines ability to block adenosine receptors has been linked to cognitive improvement in certain neurodegenerative diseases and as a protectant against Alzheimers disease, he said.

"We feel that our foot is in the door now, and this research may lead to a way to reverse early cognitive impairment in the brain. We already have drugs that target certain adenosine receptors. Our work now is to determine which receptor is the most important and use a specific antagonist to that receptor," he said.