Coffee and Health – What’s the Buzz?

Ask any Nutritional Therapist about coffee consumption and I expect that 9 times out of ten they will seek to reduce someone’s intake – as someone who does not drink coffee the idea of giving something up that I do not consume is easy. But, for many the challenge is not simply exclusion but appropriate utilisation – because as with all foods and beverages there is a bell shaped curve between benefit and loss.

The wealth of paper being published each year should I think make us all review our almost reflex response to coffee consumption and encourage us to stand back and see it as having a useful – albeit controversial role in human health and physiology.

So what are the key points to keep in mind?

All-cause mortality

After following coffee consumers for 13 years researchers published their findings in the New England Journal of Medicine and stated that coffee consumption lowered all-cause mortality by 13%.[1] They did however caution against whole hearted endorsement stating; whether this was a causal or associational finding cannot be determined from our data.

Cardiovascular disease

Every NT knows that caffeine induces an increase in blood pressure and as such generally recommend that in people with hypertension that caffeine containing beverages be excluded from the diet. Yet paradoxically when caffeine is consumed via coffee the associated antioxidants and phenolic compounds present in the beans, which reduce cholesterol and oxidation of LDL appear to generate benefits in blood pressure linked to reduced inflammation. On this analysis approximately 2 cups a day may protect against heart failure and diminish overall risk of CHD.[2],[3],[4],[5],[6],[7],[8]

The detrimental effects of coffee may be associated with the acute pressor effects, most likely due to caffeine at high daily intakes, and lipids from boiled coffee can contribute to raised serum cholesterol. Genetic polymorphisms in enzymes involved in uptake, metabolism and excretion of coffee compounds are also associated with differential biological effects.[9]

Brain health

So if we want to reduce stroke risk – there are a number of lifestyle strategies we might consider, but would we automatically say – I suggest you drink between 1-6 cups of coffee per day! Yet some studies, albeit a small number suggest preliminary benefits ranging between 17% and 25% risk reduction after long term studies may be achieved in those without pre-existing cardiovascular disease.[10],[11]

Another meta-analysis (meta-analysis is a technique whereby all data from all available studies of something are combined, often regardless of the relative quality of the data – the plan being to achieve a maximum amount of statistical information from a set of studies that might not have large enough individual sample sizes, or whose results may be of marginal statistical significance) published in 2012 suggests that the general population may see a reduction in ischaemic events with consumption of 1-3 cups a day.[12]

Meta-analysis papers are the scientific equivalent of bankers taking your hard earned money repackaging it into apparently serviceable and even attractive packages and then selling it as their own magical discovery. The result may be conflicting conversion of the data, inappropriate publication – especially if the title contains a popular theme such as coffee or food supplements, but no original work. One thing we have all been made painfully aware of, you do not improve bad data by mixing it with good – it all becomes tainted – just look at our banking industry these days. I mention all of this as meta-analysis is a very popular form of data conversion and when I am using these papers to tease out the current opinions on coffee their validity needs to kept in context.

Neurodegeneration

Many people rely on their coffee to start their morning’s cognitive processes, but some tantalising research suggests that its consumption may also offer some long term benefits. People diagnosed with a mild cognitive impairment and plasma levels of greater than 1200ng.mL of caffeine (3-5 cups per day) avoided progression, but not development.[13] Mouse models have shown coffee ingestion linked to increased IL-10 and IL-6 promotion, and these generally confer health benefits.

More sophisticated studies have shown reduction in amyloid plaque formation – linked to Parkinson’s disease, and Lewy bodies associated with the same pathology. However it has also been adversely linked to the acceleration of Huntingdon’s disease.[14]

Of interest for NT’s there is also a correlation between bowel movements, water intake Parkinson’s and Lewy bodies. Alerted gastrointestinal barrier quality and associated loss of bowel frequency may precipitate neurotoxin migration via the vagal nerve to the brain – one study found that decreased water intake and linked constipation were statically significant risk indicators for Parkinson’s development – it may be that the protective effects linked to coffee are simply those found in people who ingest more fluids and keep regular.[15],[16]  Constipation could be one of the earliest markers of the beginning of PD processes.

Blood sugar pathologies and weight

Perhaps the clinically most rampant syndrome in western societies driven by lifestyle rather than infection is “metabolic syndrome,” the dangerous cluster of hypertension, hyperglycaemia, abnormal lipid levels, and increased body fat. It seems that coffee consumption may actually impact (in a good way) on this complex presentation. Coffee drinkers it appears have improved glucose metabolism, insulin secretion, and a significantly reduced risk for type 2 diabetes.[17],[18],[19] Albeit there remains some appropriately cautious interpretations of this material when applied to a public health policy analysis.[20]

The use of unroasted coffee beans and the associated caffeine and chlorogenic acid – a compound that appears to diminish the absorption of glucose has shown – albeit in an on-going study demonstrated a remarkable 17 pounds of weight loss in 22 weeks.[21] Caution needs to be applied before rushing to seek out unroasted coffee beans high in chlorogenic acid, as it is also associated with increasing homocysteine levels in human plasma – and whilst losing fat may be a good aim, increases in homocysteine are generally regarded as a negative outcome risk![22]

Plus the normal perception that a strong cup of high-street coffee contains 50mg of caffeine can be misleading, as a recent study found a six fold variation in caffeine levels and a 17 fold variation in caffeoylquinic acid contents – mostly due to bean selection and volume.[23]

Cancer

Inevitably as we are all aware of the role of lifestyle in the risk reduction of cancer development and progression, the idea that a favourite beverage of many of our clients would add to our proposals can be attractive. Consuming 4 or more cups – keep in mind the issue about the high levels of variability per cup – seems to reduce endometrial cancer risk, head and neck cancer risk, oestrogen receptor cancer risk and basal cell cancer risk. At least in part this association maybe attributed to the antioxidant and antimutagenic properties of coffee.[24],[25],[26],[27],[28],[29]

Mood and mental health

In the female population, one paper has suggested that a doubling from 1-2 cups of coffee per day reduced depressive episodes by 15%. This increased to 20% if they consumed 4 or more.[30] The short-term effect of coffee on mood may be due to altered serotonin and dopamine activity, whereas the mechanisms behind its potential long-term effects on mood may relate to its antioxidant and anti-inflammatory properties, factors that are thought to play a role in depressive illnesses.[31]

Other linked benefits to a range of human ill health are being dragged into the research community – everyone like to be able to justify their often guilty pleasures. There are however reasonably well understood risks to consuming coffee that need to be kept in mind as well.

Coffee consumption certainly has negative medical and psychiatric effects to consider. Besides the aforementioned potential increase in blood pressure, coffee can incite or worsen anxiety, insomnia, and tremor, induce cramping, place foetus’s at risk and potentially elevate glaucoma risk. Withdrawal from caffeine intake also adversely affects many people who need to reduce their reliance of this ubiquitous drug.[32]

Although more research is clearly needed, coffee, when consumed without added cream/milk or sugar, is a calorie-free beverage that may confer health benefits, especially when used in individuals who do not have adverse subjective effects due to its stimulating effects, and when coffee is substituted for less healthy, unnatural, and/or high-calorie beverages, such as colas and other sugary and artificially sweetened sodas and soft drinks.

References