Red Wine, Caffeine and Bugs in Your Guts

Drs Chris, Dave and Helen find out why red wine is better for you than white or grape juice, and explore the science of healthy living with with Roger Corder. We also discover the...
07 January 2007



In the first show of 2007, Drs Chris, Dave and Helen find out why red wine is better for you than white wine or grape juice, and explore the science of healthy living with with London University researcher and author Roger Corder. We also discover the science behind another of the nation's favourite drugs, caffeine, with the help of Bristol University's Peter Rogers, and University of St Louis researcher Jeffrey Gordon explains how the bugs living in your intestines help you to make the most out of mealtimes. They might also, he thinks, make some people fat. Plus, in Kitchen Science, Dave demonstrates the physics of how salt keeps roads frost-free.

In this episode

Foetus-friendly Stem Cells

The practice of destroying an embryo to harvest its stem cells so they can be used to repair diseased tissues is highly controversial; some argue that it constitutes destroying life to preserve life and is unethical. But now Paolo de Coppi and his colleagues, from the Wake Forest Institute for Regenerative Medicine in Winston-Salem, US, may have discovered a more foetally-friendly form of stem cell, in the amniotic fluid that surrounds a developing baby. Writing in the journal Nature Biotechnology, the researchers describe how they have found a population of cells, dubbed AFS cells, which possess many of the same characteristics that make embryonic stem cells attractive but which can be harvested without harming the developing foetus. They make up about 1% of the cells which are naturally found floating in amniotic fluid, and they can be identified and collected using a stem cell specific marker called "c-kit". Once isolated the cells continue to divide in culture for long periods of time but without showing any signs of genetic ageing, and when injected into experimental animals they don't trigger cancers, which is a common problem with embryonic stem cells. Also, by exposing the AFS cells to a variety of chemical signals, the team were able to turn them into muscle, pancreas, liver, brain and even bone-forming cell types. The cells survived stably when they were injected into mice and the team were even able to make new bones by implanting a scaffolding coated with AFS cells. Over an 18 week period, CT scans of the implanted animals showed that the scaffold had been mineralised, but only when AFS cells were present. "Our hope is that the cells will provide a valuable resource for tissues repair and for engineered organs too", said project senior scientist Anthony Atala.

Vibrating Vests Spell Out Silent Messages

Have you ever had the feeling that your clothes are trying to talk to you? Perhaps your shirt cries out wash me or your socks scream change me! Well, actually talking clothes may not be as mad as they sound, and in fact they could have important applications for the military. So much so that scientists at the Massachusetts Institute of Technology in America are developing a vibrating vest that could give silent commands to soldiers in action. The vest contains 16 small vibrating motors imbedded into the back which respond to a remote computer and spell out a sort of back-Braille. The team led by Lynette Jones at MIT, are testing 15 vibrating codes on volunteers by trying to guide them through an obstacle course - and to great affect - nearly all of the signals have been correctly interpreted. The tactile codes include all four corners of the vest vibrating together, which means stop, and a vibrating column that moves across to the left or right, indicating which way the person should turn and other signals mean raise arms up or hop - although I'm not sure how useful that last will be in battle. These vibrating vests are showing great promise, since it could be very useful to have a way of communicating simple tasks when a soldier's hands, eyes and ears are busy doing other things. And maybe one day soldiers won't be imagining things if they think their clothes are trying to talk to them.

- The Science of Colour 3

How coloured compounds have been impotant in medicine

The Science of Colour 3
with Colour in headache cures, and treating disease - Anna Lacey

Chris - It's time now for the third part in our series on science and colour, and this week Naked Scientist Anna Lacey has been looking at how colour plays a crucial role in medicine and in the pharmaceutical industry.

Anna - I'm lucky not to get headaches that often, that is, unless I've had a beer or three too many… But for the people I asked here at Addenbrooke's hospital, there seems to be a universal cause for headaches. Stress! But regardless of whether the cause is stress or alcohol, what is it that's going on at the microscopic level when we have a headache or feel pain? Here's Dr Michael Randall from the University of Nottingham's Medical School.

Michael - We have pain receptors in the body, which can be stimulated by a chemical family called prostaglandins. And one action they have is that they sensitise those pain receptors and make them more sensitive to pain. So the body is aware of pain and inflammation.

Anna - So in order to get rid of pain, we need to get rid of these prostaglandins. But how can we do that? Well you might not have realised it, but every time you take a drug like paracetamol or aspirin, you're actually stopping the production of prostaglandins. Aspirin, for instance, locks onto the molecule that makes prostaglandin in the first place - and if you stop prostaglandin production, then you stop the pain. But what's this got to do with the science of colour? Well last time I talked about how coal tar gave rise to the colour mauve, which was the very first synthetic dye. Now it turns out that chemicals derived from coal tar were also used in the development of aspirin and paracetamol - so bizarrely both our high streets shops AND medicine cabinets have benefited from the same black goo. Now that all happened in the 19th and early 20th century, but colour's still vital in cutting edge treatments even today - and one of these is called photodynamic therapy. So what's that all about? Here's Professor Stan Brown, the director of the Centre for Photobiology and Photodynamic Therapy at the University of Leeds.

Stan - Photodynamic therapy is a newly developing approach for the treatment of a variety of diseases including cancer and infectious diseases, which uses a coloured drug that in itself is harmless, but is activated when you shine light on it. When the drug is in the target, which could be a tumour or a bacterial cell for example, we shine the light on to the target. The drug, or the photosensitiser as we sometimes call it, then absorbs the light and takes in the energy from that light. That energy is then passed on to ordinary molecular oxygen, which is everywhere, including inside the body. The trick is that this energy then converts the oxygen into a very activated form, which destroys the cells immediately around it, but no further than that.

Anna - So what colour are these photosensitising dyes?

Stan - Ideally we try to have blue dyes. They're usually a beautiful colour of blue, so it's quite an interesting area to work in for clinicians as well as scientists. They're blue because they absorb red light, and the reason we use red light is that it penetrates into the tissue much more deeply than other colours of light. An example of that that I always point out is that if you point a torch through your hand, it comes out red. That's not the colour of blood as we always used to think, but it's because all of the colours except red are absorbed while red penetrates and comes out the other side. So that shows why we use red light, and therefore why we use blue drugs.

Anna - Photodynamic therapy, or PDT, is proving to be very successful in the treatment of macular degeneration and in the future, is likely to be developed further for cancers and killing off superbugs like MRSA. If you want to hear more about photodynamic therapy, then you can go to our website -, to hear the full-length interview. Well if that dose of colour science wasn't enough, you can join me next week when I'll be looking at why wearing red will win you running races and how colour affects our mood.

- The Wine Diet: Is Red Wine Good For You?

What is the truth behind all the stories in the papers about the health benefits of red wine, Roger Corder explains.

The Wine Diet: Is Red Wine Good For You?
with Roger Corder, from the Royal London School of Medicine

Chris - One of the things you've risen to prominence for Roger is sussing out what's in red wine that makes it good for us.

Roger - Absolutely, that's been my work for the past six or seven years. I've focused on finding out what is in wine that improves blood vessel function and protects from heart disease.

Chris - So how did you go about that and what is the bottom line? Is it good for us?

Roger - All the evidence points to it being good for us. But it may be that certain types of wine are much better than other wines. What we did from a laboratory point of view is we studied exactly what substances in wine could change blood vessel function. In parallel with that we were looking at areas where people were living longer and drinking wine. And we saw that the wines in these areas were richer in a substance we identified, procyanidin, which is a flavanoid polyphenol. People would know them as anti-oxidants but in terms of the effects that we were looking at, this causes a profound change in blood vessel function.

Chris - There is a phenomenon called the Mediterranean Effect isn't there for people from the Mediterranean basin. And the French paradox as well. There are French people who manage to have an atrocious diet, smoke like chimneys, and live to be 500 years old. No one really understood how they did it, and what you're saying is that it's the red wine that they're drinking.

Roger - Exactly. The Mediterranean diet sprung out of research called the seven country study. That showed that people living on the island of Crete were living longer with less heart disease despite a fairly high fat diet. But an important part of their diet was to drink regular wine. Now I started to look at Sardinia because the highest concentration of centenarians were based on this island in terms of European population, and I found that their wines were richer in Procyanidins than wines from other areas. The Cretan wines were also particularly rich in this particular polyphenol. And so I then looked at the French population. And there's a regional variation in heart disease across France. And there's also a regional variation in terms of longevity. And what I found was that people living in South West France were drinking wines which were very rich in these polyphenols. But the interesting thing about this and the French paradox, is that this is one of the areas of France where they eat some of the fattiest foods. And so I became convinced that a) Wine should be part of a healthy diet, and b) some of the nutritional advice being pushed on the general public was actually not based on fact.

Chris - Is there a conflict of interest here Roger, because you're a wine connoisseur aren't you?

Roger - I wouldn't like to say I'm a wine connoisseur. Obviously we all like to have excuses for our habits. What I was, was somebody who was religiously following a low fat diet. And I suddenly started looking at the science of low fat diets, and realised that actually, if you wanted to have a healthy cholesterol level, it was the type of fats you ate, rather than having a low fat diet. Low fat diets are often boosting over-purified carbohydrates into people's food, and sugar into people's food. And that was actually changing their heart disease risk in an unfavorable way. And so this drove me to write a book to explain what it is about eating healthily that everybody should understand. It doesn't matter whether you're thin or fat. Wine can be part of it, but the food you eat is so crucial to your overall wellbeing.

Chris - Let's just focus in on the wine story for a second. You saw this effect, which was distributed across France, and the effect rose specifically in South West France. So what was going on there that meant that people, despite an atrocious diet, were protected? Presumably it wasn't just genetic.

Roger - I wouldn't say their diet was atrocious, it was just different. Essentially they were growing a grape down there called the Tannat grape that was very very rich in these protective polyphenols. But other wines are also good for you.

Chris - Is it just red wine though Roger? Because lots of people say you have to drink red wine, white wine's no good. Beer's no good.

Roger - Well, let me provide you with some evidence. Alsace has the lowest longevity in France. And it has some of the highest heart disease. That's a white wine drinking area.

Chris - So it is specific to the colour. Red wine grapes impart the protective chemicals.

Roger - Exactly.

Chris - What are those chemicals, how do they work and how does the grape make them?

Roger - Actually white grapes also have them. The difference between white wine and red wine is really the way in which the wines are made. The white wine is the fermented juice of the grape, where red wine is the fermented juice with the seeds and skin present. So the longer the time of the fermentation with the seeds, the more extraction of these polyphenols that you have. And so the higher the levels.

Chris - Ok so we know wine has this stuff in it. How do we actually get this stuff to where it needs to go, the blood vessels? Why does if affect your risk of vascular disease? How does it work?

Roger - Essentially, if you imagine that blood vessels are a tube, and they have a lining which is protective. It's important that they function in a healthy way. Now the chemicals in wine are able to boost the healthy characteristics of this lining. So that you reduce your risk of heart disease. Many people may be aware that chocolate has also been said to be helpful. Now the point about chocolate is that dark chocolate has the same polyphenols in, as a good red wine. As so for non wine drinkers, if they want to get these polyphenols into their diet from other sources then dark chocolate becomes a possibility.

Helen - So I bet people out there are dying to know. Can we say in a snapshot, what should people be eating? And how many glasses of red wine should I be drinking? Is there enough in one glass?

Roger - If you look at a glass of average supermarket wine there isn't probably enough to have much benefit. But with time we're going to change people's awareness of wine and also the way that it's labeled. If there was more details about the wine making process, one could read the label and think that if it's been fermented a long time it's much more likely to have a higher level of these compounds. But there's no information on wine. How much should you drink? All the scientific evidence about reduced heart disease actually reflects a consumption level that is similar to what government guidelines recommend. So for a woman that's no more than one to two small glasses per day, 125 mL. For a man, two to three glasses is ok. But an important factor about people benefiting from wine consumption is that it's part of a lifestyle pattern. It's not going to the pub and shoving down a few glasses of wine and then thinking, "I've got all the benefits". Because studies have shown that people who drink without food are more likely to have high blood pressure. High blood pressure increases your risk of heart disease and it increases the risk of a stroke. So it's important to understand fully, the lifestyle combinations.

See also 
Roger Corder's book "The Wine Diet", which will point you in the direction of the healthiest red wines to have at dinner time.

- Why Caffeine Tastes So Good

The science of caffeine, what is it doing to us? Is it addictive? Is it bad for us?

Why Caffeine Tastes So Good
with Peter Rogers from Bristol University

Chris - Our other guest this evening is Peter Rogers from the University of Bristol and Peter works on caffeine, amongst other things. It's my favourite drug for certain, so what's it doing to my body?

Peter - Well indeed it's the world's favourite drug, so it's easily the most widely consumed drug globally and therefore very important. So what's it doing to us? It has some pretty fundamental biological actions and has affects accordingly on many organs and tissues in our body, including the brain. It's affects are quite surprising and not what we think they are. For a start, the most obvious thing we think about caffeine is that we get stimulated by it. Certainly, we feel that stimulation when we wake up in the morning and have that first cup of tea or coffee.

Chris - It's pretty addictive isn't it?

Peter - Well I wouldn't use the word addiction with caffeine at all. I think addiction should be reserved for when there's compulsive use and so on.

Chris - I think my usage is pretty compulsive!

Peter - Well you probably consume it frequently but I think you could probably give it up quite easily.

Chris - Someone once put a jar of decaff in my cupboard and I didn't realise and went round with a headache for a week.

Peter - Yes, now that shows that you're physically dependent on caffeine, and I would say that caffeine causes dependence. You'd probably need about a week to get over the dependency, so it's quite easy to give up. The key thing is that in terms of your acute day-to-day functioning, you're probably functioning just as well without caffeine as you are with it once you've got over that initial withdrawal.

Chris - That perpetual headache, a feeling of lassitude and tiredness, an inability to concentrate, words gets tangled up in your head: it's got all the hallmarks of an addiction. When I drink this coffee here, when I take that into my body, what's actually happening?

Peter - What caffeine is doing is blocking adenosine receptors; cell surface receptors on cells in our brain and other organs in our body. Those cells' receptor are normally activated by adenosine that's produced by the body. Adenosine levels are actually increased during wakefulness and decreased during sleep. By blocking the effects of adenosine at those receptors, caffeine is keeping us stimulated and awake. An important issue is that with regular consumption of caffeine, that system adjusts itself. That system becomes more sensitive to the effects of endogenous adenosine, and we've shown in our experiments, that with regular consumption we're not actually getting a net benefit for our alertness and mood from consuming caffeine because of this readjustment of physiology.

Chris - So it has an effect for a little while and that wears off, so you're back to square one and you need the drug to feel normal.

Peter - You are. We've pretty much clearly shown that the buzz you feel in the morning is what we call 'withdraw-reverse'. So overnight you metabolise away the caffeine you consumed the previous day and you wake up feeling tired and lethargic, even after a good night's sleep. This is when you're in the early stages of caffeine withdrawal. Your caffeine in the morning picks you up and brings you back to normal, but not above normal.

Chris - Lots of these cold remedies you take when you have a cold are loaded with caffeine. The reason you feel so pepped up is that there's a microscopic dose of paracetamol, a whiff of aspirin and a massive slug of caffeine.

Peter - It's not got a massive slug. It's probably got a cup of coffee equivalent slug of caffeine in there, and that's obviously a misnomer, such as the idea of energy drinks having massive amounts of caffeine. You could get the equivalent amount of caffeine from an energy drink but much more cheaply. It's interesting that it's in analgesics and flu remedies. The benefit there is that you're reversing caffeine withdrawal again, because actually when you've got the flu, you don't feel much like drinking tea and coffee, so that's your replacement caffeine.

Chris - It's very good for people who want to sell you something. If you feel much better because all it's doing is pandering to your addiction, it's not really making you feel better at all, is it?

Peter - Well it's getting you back to normal. I would argue that you'd be better without consuming caffeine on a daily basis, although there are some longer term studies of caffeine that are very interesting.

Chris - That was going to lead me onto the next thing, which is: is this bad for us? We're all drinking this stuff, so if caffeine health deleterious?

Peter - I think it should be put in perspective and there are lots of other things that I would do first in terms of my behaviour to improve my longevity than giving up caffeine. All too often people say that of there's something wrong with you, you should give up caffeine. I think that's not the right approach to take because tea and coffee are actually part of our lives and they're enjoyable, so if there's no reason to give it up, don't give it up.

Chris - Is there any evidence that it is bad for you? They must have done some trial.

Peter - The greatest worry in terms of my understanding of the literature is concerned is that caffeine increases blood pressure, and we've already heard how that increases the risk of cardiovascular disease for example. But there's a lot of discussion about those effects. There are obviously these short-term caffeine effects such as caffeine withdrawal, which is not good for our everyday functioning. There are some interesting results suggesting that long-term caffeine consumption may be protective against cognitive decline later in life, and there's also evidence that it may be protective in relation to the risk of Parkinson's disease.

Chris - I think people have said, though, that smoking can protect you against Parkinson's and Alzheimer's, and cynics have said that it's because people who smoke don't live long enough to get those diseases. So maybe in caffeine's case, one could argue that there is a beneficial effect.

Peter - I think there is in relation to caffeine, and I don't think that that's a good explanation either, the smoking data or the caffeine data. There are good reasons to believe how caffeine may interact with Parkinson's disease because adenosine interacts with dopamine in the brain, and adenosine normally puts a break on dopamine function. So caffeine blocking that adenosine function may de-inhibit dopamine action, which is impaired in Parkinson's disease for example. So there are plausible mechanisms whereby caffeine could be protective with regards to the adenosine system and also in relation to Parkinson's disease.

- Stomach Microbes And Weight Gain

How the bacteria in your guts could affect how much energy you get from your food, and hence obesity.

Stomach Microbes And Weight Gain
with Jeffrey Gordon from Washington University

Chris - Tell us about your study and how you discovered a link between stomach bacteria and weight gain.

Jeffrey - Let me start out with a sobering or inspiring thought depending upon your perspective. Adult humans are composed of ten times more microbes than they are human cells. Now the question is what do these microbes do to us, how do they benefit us, how do they form strategic partnerships with us? We began this study using a good stand in for humans, the laboratory mouse. We took a look at genetically obese mice and their lean litter mates. And found that the principle bacterial groups in the gut, so called Firmicutes and Bacteroidetes, were present in different proportions in the obese, compared to the lean mice.

Chris - Is that just because these animals have been genetically tinkered with to make them fatter?

Jeffrey - The implications are that there may have been a link between the amount of fat and the composition of the microbial community. We did another series of experiments and took the communities from obese mice and started sequencing the genes from those communities. Then compared the gene content of the obese community to the gene content of the lean gut community. Again this is in mice. And we found that the obese mouse community had a greater capacity to break down certain components of our diet that are difficult to digest with our own enzymes.

Chris - So the bacteria are lending their genes to our gut? So the bacteria, by breaking down food we can't normally access are feeding us additional calories.

Jeffrey - Well there's an increased efficiency of breaking down these components of our diet, which are called polysaccharides. These are complex sugars. The idea spawned from these experiments was that perhaps when people sit down with a bowl of cereal in front of them, which are rich in polysaccharides, that some individuals are able to extract more calories than their dining partners, who had a different suite of microbes. So even thought the package labels may say 110 Calories per serving size, that's an absolute value. In the real world, depending upon your gut microbes, you may have slightly more or slightly fewer calories delivered to your body as a result.

Chris - So you've looked in mice and found this relationship, mice that are fatter have a different spectrum of bugs in their gut, they get more energy out of their food, and this might be contributing to weight gain in the mice. But what about in humans, is the same true?

Jeffrey - We've recently taken a group of 12 human volunteers, all obese, and put them on one of two types of low calorie diet. One where fat was restricted, and one where carbohydrates were restricted. And we looked at their gut microbes, before they began this diet, and during the time that they lost weight. And we found that just like in obese mice, these gut microbes that are more abundant in the mice are also more abundant in obese human guts. And those that are diminished are also diminished in obese human gut. And the more diminutive group begins to expand as you lose weight. Interestingly, it's not just one member of these groups that are changed, it's the whole group that shifts in its relative abundance. So there seems to be a dynamic linkage to the amount of adipose tissue you have, and the nature of your gut microbe community.

Chris - Now what happens if you take that spectrum of bugs that live in a fat mouse, and colonise the gut of a mouse with a different community of gut bugs, that's slim? Does it gain weight?

Jeffrey - A very good question. You can raise mice under completely sterile conditions; they're called germ - free animals, to adulthood. And then you can do a microbial community transplant. You can take a microbial community from an obese mouse and transplant into one of these germ-free animals, and observe how much fat they gain over time. And you can do the same thing where the donor is a lean mouse. And just as you imply, the obese gut microbial community is able to direct a greater increase in fat than the lean community. So this characteristic is transmissible. What we don't know is whether some people start out, even before they become obese, with a slightly greater amount of one group, that we call the Firmicutes, and a more diminished amount of the Bacteroidetes. And whether they're predisposed, depending on their diet, to extracting more calories.

Chris - I guess that's what you'll look at next.

Jeffrey - Absolutely. And we have to really understand what these groups of different bacteria bring to the dining room table. It's really part of a larger attempt to understand how these alliances between humans and that our microbial companions benefit us. And whether there are differences in our microbial community structures that impart to each one of us distinctive physiological characteristics.

E.coli bacteria

- Science Update - Bacteria

The Naked Scientists spoke to Chelsea Wald and Bob Hirshon, AAAS, the Science Society

Science Update - Bacteria
with Chelsea Wald and Bob Hirshon, AAAS, the Science Society

Bob - This week for the Naked Scientists, we're going to talk not about the bacteria in your gut, but in the air all around you. As Chelsea tells us, these bacteria have become a matter of a national security.

Chelsea - If there's anthrax in the air, is it a bioterror weapon, or just a harmless, naturally occurring close relative? The Department of Homeland Security needs to know, so they asked scientists at Lawrence Berkeley National Laboratory to take stock of the air's normal bacteria population. Microbial ecologist Gary Andersen says a better sampling technique was sorely needed.

Gary - Virtually everything that has been done to date has used culture. And we know for a fact that less than 1 percent of all organisms that are in the air, like most environments, can be cultured.

Chelsea - Instead, his team used DNA microchips. They're about the size of a quarter, and capable of distinguishing thousands of bacterial species from a single gene. Their first census of the air over Austin and San Antonio found incredible diversity: about 1,800 kinds of bacteria. And the demographics were by no means static.

Gary - We see that the bacterial organisms in the air change and respond to environmental conditions. When the temperature of a typical week was warmer or windier, we had completely different types of organisms that were present than during other meteorological conditions.

Chelsea - By understanding natural variations like these, and eventually expanding the census nationwide, the scientists hope to get the first reliable baseline of airborne bacteria. This can be useful not only for spotting possible terrorist attacks, but also for watching how global warming and climate change can affect the microbes in the air, and potentially, the public health.

Bob - Thanks, Chelsea. And we have some other news about our air. Thanks to a massive international effort, the atmosphere's damaged ozone layer is just starting to heal. Now, scientists have a better way to check up on it. Physicist Eric Muller of Lockheed Martin Coherent Technologies in Colorado has helped develop a laser-enhanced satellite system for measuring an atmospheric chemical called OH. Muller explains that OH is not only a key marker of the ozone layer's health -- it's also useful for validating scientific models of the whole atmosphere.

Eric - It turns out that how good the model is at predicting OH tells you a lot about how good the model is at predicting all kinds of other things.

Bob - And having reliable models will be critical in deciding how to respond to complex phenomena like global warming.

Chelsea - Thanks, Bob. Next time we'll talk about new research that shows that tiny distractions can be worse for your focus than big ones. Until then, I'm Chelsea Wald.

Bob - And I'm Bob Hirshon, for AAAS, The Science Society. Back to you, Naked Scientists.

- Are liquidised vegetables good for you?

It's recommended that we eat 5 portions of fruit and vegetables a day. So I'd like to know, if I liquidise all of my portions into one, a...

Are liquidised vegetables good for you?

I wouldn't suggest drinking them all at once but I think that over the period of a day you would get the same benefit. I think what's important about the five fruit and vegetables a day is not necessarily only the fibre, but also all the nutrients that are in these foods. These nutrients help reduce your risk of heart disease and cancer. And that's what much more important than the fibre. Eating a high fibre breakfast cereal, doesn't reduce colon cancer. Studies have shown that. It's the nutrients in people's diets that are high in fibre that are more important.

- How can icebergs survive in the sea?

Everybody knows that salt melts ice. Why are there such big icebergs in the sea?

How can icebergs survive in the sea?

Salt makes ice melt at a lower temperature. So in sea water ice will melt at maybe -5 or -6 degrees centigrade. But if you get cold enough, the water will still freeze. And so you can still get icebergs. It's just got to be a bit colder than if it was in a lake. When there's salt in water, the water can get a bit lost in the salt. It gets in the way of the water forming a crystal. It's more difficult for the water to form the crystal, so it has to be a bit colder for it to actually freeze.

- Are old vegetables as good as fresh?

If we store seasonal fruit and vegetables will they still have all the same nutrients as when they're fresh?

Are old vegetables as good as fresh?

Well certainly the mineral content isn't going to change. But it's likely that some vitamins will decrease over time. So there is an optimal time when you can eat these foods. It really depends on the storage environment. If it's a cold environment then it's going to slow the degradation of things like vitamin C and other minerals that are unstable.

- Does your body make cholesterol?

If you don't eat enough cholesterol - does your body not just make it anyway?

Does your body make cholesterol?

The idea that you should have a low cholesterol diet to lower your cholesterol is completely flawed. In fact if you eat a low fat diet and have lots of refined carbohydrates, then your body likes to make cholesterol out of those excess carbohydrates. So a low fat diet isn't the secret to lowering cholesterol levels.

- Is sherry good for us as well as red wine?

If red wine is good for us, is sherry good too?

Is sherry good for us as well as red wine?

Well sherry's quite a rich source of alcohol. But I think it's got to be taken in the context of your overall sense of well being. Don't drink too much and make sure other aspects of your life are healthy. Unfortunately it doesn't contain the same specific healthy components that red wine does.

- Does peanut butter help to lower your cholesterol?

Does peanut butter help to lower your cholesterol?

Does peanut butter help to lower your cholesterol?

I haven't actually studied any literature on this but certainly peanut butter is a source of mono-unsaturated and polyunsaturated fat. So in the context of a balanced diet, it is likely to have some beneficial effect if you are at the same time cutting out saturated fat. So it's really about replacing say the amount of red meat you might be eating with things that are rich in vegetable fats. Another good example of this would be Soya beans. Soya beans are a good source of vegetable fats.

- Do high roasted coffee beans cause cancer?

Do high roasted coffee beans cause cancer?

Do high roasted coffee beans cause cancer?

I'm not aware of any evidence that that's the case. The evidence for coffee and cancer is pretty good. It's neither protective nor harmful. The method by which you prepare coffee is quite important, so filtering coffee takes out some of the cholesterol elevating effects of coffee. So boiled coffee is not a good way to prepare it. Cholesterol raising oils are also not present in instant coffee.

- What causes the tremor from coffee?

What causes the tremor seen in heavy coffee drinkers, and is that related to dopamine like with Parkinson's Disease?

What causes the tremor from coffee?

That's a very interesting question indeed. There's a bit of a paradox. In healthy people, caffeine causes a bit of a tremor in your hands, it reduces hand steadiness. Whereas there's evidence that it can protect against Parkinson's disease.


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