Science Catch-up. Coffee: How Many Cups?


by Alejandra "Alex" Ruani — Get free science updates here.

Welcome to our Thursday Science Catch-up: curated links by The Health Sciences Academy. Get our email updates every other Thursday here (it’s free).

Let’s catch you up with studies and news that recently made the headlines!

Click on your favourite topics to read our summary:

1. Coffee: How many cups?

2. Mindfulness for weight loss: Esoteric fad or scientific fact?

3. Cheese for heart health… really?

4. Wait, obese brains look different?

5. Breakfast-skipping, epigenetics and fat cells: what’s the link?

 

Coffee: How many cups?

Study link

New coffee research sheds light on benefits (Poole et al., 2017).

Are you one of billions of other people that cannot live without their daily cup of joe?

We see new coffee-friendly research published every week, but this one grabbed my attention because it’s a systematic review that pooled several meta-analyses (a study of studies of studies)…

In fact, a whopping total of 218 meta-analyses were captured in this huge investigation called an “umbrella study”.

After going through all data sets, the researchers concluded that gobbling down 3 to 4 small daily cups of coffee (including decaf!) was associated with reduced risks of type 2 diabetes and oral cancer.

They suggest that the high antioxidant content of both caffeinated and decaffeinated coffee might be responsible for such benefits.

For example, polyphenols in coffee such as caffeic acid may interfere with oxidative stress processes and consequently improve insulin sensitivity in cells, thereby lowering the odds of developing insulin resistance.

Increased coffee consumption (up to 4 cups a day) was associated with a reduced risk of several medical complications (Poole et al., 2017).

How much coffee (or caffeine) in each cap?

Unfortunately, the review doesn’t say…

The European Food Safety Authority generally regards a maximum caffeine intake of 400mg daily to be safe in healthy adults.

This is roughly the equivalent to drinking a maximum of 3 espressos of 30ml each, or 4 small cappuccino mugs of 180ml each.

While the study showed that regularly drinking coffee conferred some benefits, the risk of stillbirth and miscarriages in pregnant women was significantly increased at 1 to 8 daily cups, compared to non-drinkers.

Note: Whether you’re a coffee lover or not may have some genetic explanation after all! If you want to get the full scoop on how eight “coffee genes” may influence your coffee addiction, detoxification, and metabolization, then you may want to grab this roasty Science Report: Nutrigenomics 101: Coffee and Your Genes (optional resource).

 

 

Mindfulness for weight loss: Esoteric fad or scientific fact?

Study link

Relationship between eating behaviour and weight loss. Hedge’s g is a measurement of effect size commonly used in meta-analysis (Carriere et al., 2017).

New Year is just around the corner and many people are thinking about embarking on a weight-loss adventure, even if that means trying the alternative methods…

But could something as abstract as mindfulness help to thin that waistline?

Mindfulness can be described as a state of intense focus through all 5 senses on a present experience, and it has been studied by psychological researchers since the 1970s.

In this new Canadian meta-analysis, it’s suggested that this practice could serve to stimulate healthier eating behaviours, which can in turn help with weight loss.

The question is, how?

When analysing 19 mindfulness interventions from 1,160 participants, the results showed reduced behaviours associated with binge eating, often occurring on the back of anxiety and emotional distress.

Indeed, mindfulness worked in two ways:

  • It reduced negative thoughts that encourage overeating
  • It improved resilience against hunger pangs during dieting

What about weight loss?

The Canadian researchers reported a weight loss of up to 7.5lb (3.4kg) in 16 weeks. That said, when looking at the data, we can’t tell for sure if there were other factors influencing this, such as lower caloric intake or exercise.

While not everyone may benefit from mindfulness in the same way, combined with the fact that there are thousands of mindfulness techniques, it’s still interesting to see new research on this as a complementary approach. At the end of the day, it is free and pain free.

 

Cheese for heart health… really?

Study link

You may have seen recent news praising the heart-health benefits of eating cheese…

But some may wonder, “how can this be possible when cheese is full of saturated fat and calories?”

To see what’s going on, we sliced the study behind the headline for you!

So here you go:

A group of Chinese researchers investigated the effects of cheese on heart disease risk.

They did this by pooling data from 15 observational studies on people’s cheese consumption and their corresponding cardiovascular outcomes. So far, so good.

However, unlike what’s been reported in the news, what the researchers really wanted to find was the ideal “cheese dose”…

This means they didn’t compare eating cheese vs eating tofu, for example.

In other words, all we have here is cheesy data. Very relevant if you are a cheese lover, though!

Then… what’s that ideal “daily dose” of cheese for heart health?

In this analysis, 40 grams a day conferred the greatest cardiovascular risk reduction.

The curve’s lowest point indicates the daily “dose” of cheese with the lowest risk of heart disease was at approximately 40 grams per day – a matchbox size (Chen et al., 2017).

But eating smaller quantities (below 40 grams) translated into a higher heart risk.

How is that even possible?

Well you see, it is believed that the high content of calcium in cheese could be behind its benefits.

Because calcium causes saturated fatty acids and cholesterol in cheese to precipitate (become insoluble), which makes it much harder for the body to absorb them…

And if that explanation wasn’t fascinating enough, the presence of beneficial bacteria (probiotics) in cheese has been suggested to improve blood lipid profiles such as HDL cholesterol, associated with lower risk of heart disease.

While the study mostly included semi-hard and full-fat cheeses, I’d be interested to see new research on the effects of other cheese types, like low-fat cream-cheese.

 

Wait, obese brains look different?

News link

Disruption in the white matter of obese participants vs healthy controls (Bertolazzi et al., 2017).

By now you’re probably aware that being above a certain BMI range (18.5-24.9) increases the risk of a myriad of conditions, including metabolic syndrome, type 2 diabetes, and heart disease.

But can obesity also affect brain function?

In a new type of investigation, an advanced type of MRI scan known as DTI (diffusion tensor imaging) was used to compare the brains of obese and healthy-weight adolescents.

What the scientists discovered was concerning…

They saw multiple alterations in the white matter of obese participants, compared to the healthy controls.

But, what is white matter? And does it matter?!

White matter is brain tissue that is important for information exchange and learning processes.

It was worrying to see that the brains of obese participants had alterations in white matter areas known to be involved in appetite control, emotional regulation, and food reward.

Ultimately, these brain changes may help to better explain why obese individuals often struggle to lose weight despite their best efforts.

This study was particularly interesting because it makes us more aware of the extraordinary brain-diet loop that exists, and how we may be able to go about appetite control as we unravel the workarounds of our brain.

Note: Ever wondered how our brains make decisions about food? And how can you make better decisions? Check out our Science Report: How Does Your Brain Make Food Decisions? (optional resource)

 

 

Breakfast-skipping, epigenetics and fat cells: what’s the link?

Study link

Epigenetic effects of breakfast-skipping (Gonzalez et al., 2017).

Are you a breakfast eater or skipper?

If you are someone who prefers skipping breakfast with the hope to improve metabolic health, you’ll love to hear that there is some scientific basis to this…

In this new trial, 48 healthy lean and obese participants were randomised to either eating breakfast or fasting until midday for 6 weeks.

The scientists’ objective was to explore the differential effects of having breakfast vs fasting on adipose tissue gene expression.

Changes in the production of the glucose transporter GLUT4 in response to fasting (Gonzalez et al., 2017).

Adipose tissue is the body’s warehouse of fat. It is primarily composed of adipocytes: cells filled up with enormous fat droplets.

The study revealed that fasting activated fat-cell genes involved in improving insulin sensitivity and lipid turnover in adipocytes, compared to those who ate breakfast.

Interestingly, these differences were only true in the lean subjects.

This is because fat stores in the obese are already large enough so an adaptation inhibits the adipocytes from engulfing more glucose and fat, preventing them from getting any bigger.

Note: What if you are a regular exerciser or body builder? Is fasted training beneficial or detrimental? We navigate the latest evidence to answer this question in our Science Report: Fasting and Training: Good or Bad? (optional resource)

 

 

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The-Health-Sciences-Academy-Alejandra-Ruani-small1-right Alejandra "Alex" Ruani leads the research division at The Health Sciences Academy, where she and her team make sense of complex scientific literature and translate it into easy-to-understand practical concepts for their students. She is a Harvard-trained scientist and UCL doctoral researcher who specialises in cravings and appetite neurobiology, nutrition biochemistry, and nutrigenomics. Besides investigating and teaching the latest advances in health and nutrition science, Alex makes it easier to be smarter with her free Science Catch-ups.

Connect with Alex via email.


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