You may remember a previous post that showed how ice cream can be extremely addictive. When I saw this (art) it made me laugh. I hope you find it amusing.
Eating well can keep your body strong–but can food choices actually shield you from devastating diseases like cancer? Charlotte Kellogg, who writes around the web about a variety of public health programs and nutrition-related topics, debunks five “food myths” in the post below. Her article builds on prior Wonder Food articles about the power, both real and perceived, of a balanced diet.
Public Health Myths: 5 Foods That Don’t Cure Cancer
According to a recent report by Daily Mail Online contributor Emily Allen, 10 percent of adults believe that certain healthy foods and beverages (known as “superfoods”) can prevent or minimize one’s risk of cancer. However, medical experts warn there is no evidence that these edible items carry any cancer-preventing properties – and historically, research studies that make such claims have been highly inconclusive. Today, doctors warn that the following five superfoods, while somewhat nutritious, should not be relied upon to cure cancer.
Though studies show that eating regular quantities of raw almonds can help people lower their cholesterol and lose weight, the nuts’ status as a cancer-preventing superfood has been disputed in recent years. Almonds are high in fiber, and this can greatly improve the health of one’s colon. However, researchers have been unable to establish a definitive link between eating almonds (or even keeping a high-fiber diet) and significantly lowered risk of colon cancer.
In recent years, several studies have touted acai berries as an effective (and delicious) cancer-fighting agent. But according to a Yahoo! Voices article titled “Acai Berries and Cancer Prevention,” this claim is somewhat misleading. Acai berries are rich in antioxidants, moreso than most other foods. Researchers have established a link between high antioxidant intake and reduced stress among cancer patients, as well as the reversal of cell damage. However, there is no evidence that acai berries actually prevent cancer from occurring in individuals who consume them.
A 2010 study conducted at Louisiana State University proclaimed black rice was arguably the most effective superfood ever, primarily due to its high content of both fiber and antioxidants. However, neither of these nutrients has been officially linked to any concrete cancer prevention. And as Allen noted, the fiber content of black rice is on par with that of whole-grain rice, which is much more cost-effective.
Within the last few years, several publications – including Science Daily – have reported that pomegranate juice could effectively reduce one’s risk of prostate cancer. However, a recent CBS News article titled, “Prostate Cancer Self-Defense: 9 Deadly Myths” noted that the studies supporting this claim are somewhat inconclusive because they were performed in a test tube – not on a living patient. “If you’re at a high risk for the disease, you could try it,” said Dr. Herbert Loper, director of the Smilow Comprehensive Prostate Cancer Center at New York University Langone Medical Center. “But try it without a false sense of expectation.”
Though a key study reported that the high antioxidant content in raw popcorn can prevent cancer in those that consume it, Dr. Tom Smith of Guardian UK recently pointed out a key aspect of this study – it used animal, not human, test subjects. “There’s a big problem in extrapolating from results reported in animals to human beings,” he wrote. “We are very far from knowing how popcorn might change the risk of cancer in people, if it does at all.” He added that high intake of popcorn can actually lead to weight-related medical issues, such as obesity or diabetes.
Researchers at King’s College London, Harvard University and Massachusetts General Hospital have identified for the first time a key factor responsible for declining muscle repair during ageing, and discovered how to halt the process in mice with a common drug.
Although an early study, the finding provides clues as to how muscles lose mass with age, which can result in weakness that affects mobility and may cause falls.
Published today in the journal Nature, and funded by the Biotechnology, and Biological Sciences Research Council, Harvard Stem Cell Institute and National Institutes of Health (US), the study looked at stem cells found inside muscle – which are responsible for repairing injury – to find out why the ability of muscles to regenerate declines with age. A dormant reservoir of stem cells is present inside every muscle, ready to be activated by exercise and injury to repair any damage. When needed, these cells divide into hundreds of new muscle fibres that repair the muscle. At the end of the repairing process some of these cells also replenish the pool of dormant stem cells so that the muscle retains the ability to repair itself again and again.
The researchers carried out a study on old mice and found the number of dormant stem cells present in the pool reduces with age, which could explain the decline in the muscle’s ability to repair and regenerate as it gets older. When these old muscles were screened the team found high levels of FGF2, a protein that has the ability to stimulate cells to divide. While encouraging stem cells to divide and repair muscle is a normal and crucial process, they found that FGF2 could also awaken the dormant pool of stem cells even when they were not needed. The continued activation of dormant stem cells meant the pool was depleted over time, so when the muscle really needed stem cells to repair itself the muscle was unable to respond properly.
Following this finding, the researchers attempted to inhibit FGF2 in old muscles to prevent the stem cell pool from being kick-started into action unnecessarily. By administering a common FGF2 inhibitor drug they were able to inhibit the decline in the number of muscle stem cells in the mice. Dr Albert Basson, Senior Lecturer from the Department of Craniofacial Development and Stem Cell Biology at the King’s College London Dental Institute, said: ‘Preventing or reversing muscle wasting in old age in humans is still a way off, but this study has for the first time revealed a process which could be responsible for age-related muscle wasting, which is extremely exciting. ‘The finding opens up the possibility that one day we could develop treatments to make old muscles young again. If we could do this, we may be able to enable people to live more mobile, independent lives as they age.’ Dr Andrew Brack, senior and corresponding author of the study from Harvard University, said: ‘Analogous to the importance of recovery for athletes training for a sporting event, we now know that it is essential for adult stem cells to rest between bouts of expenditure. Preventing stem cell recuperation leads to their eventual demise.’ Kieran Jones, co-author of the study from King’s, added: ‘We do not yet know how or why levels of the protein FGF2 increase with age, triggering stem cells to be activated when they are not needed. This is something that needs to be explored. ‘The next step is to analyse old muscle in humans to see if the same mechanism could be responsible for stem cell depletion in human muscle fibres, leading to loss of mass and wastage.’
Following from my previous post on organic tomatoes, here’s a post from Michigan State University on how wild tomatoes are stronger than their domestic cousins.
Domestic tomatoes could re-learn a thing or two from their wild cousins—like how to fight off bugs.
Long-term cultivation has led to tomato crops losing beneficial traits
common to wild tomatoes. Anthony Schilmiller, Michigan State University
research assistant professor of biochemistry and molecular biology, was
able to identify a gene that is involved in one of these beneficial
Trichomes, or hair-like protrusions, produce a mixture of specialized chemicals that shape the interactions between the plant and its environment. The location of the chemicals allows some of them to act as the first line of defense against pests.
One class of compounds, acyl sugars, is a frontline defender. Trichomes secrete acyl sugars to fend off pests. Schilmiller teamed with Robert Last, professor of biochemistry and molecular biology, and Amanda Charbonneau, doctoral researcher, to try to understand how these chemicals are made. Their findings appear on the cover of this week’s Proceedings of the National Academy of Sciences.
Little was known about how acyl sugars were produced until now, and this research identifies and describes the first gene that participates in the production of the protective sugars in cultivated tomatoes, Schilmiller says.
“Acyl sugars play a critical role in allowing wild tomatoes to fend off bugs,” he says. “Because cultivated tomatoes were not bred for their acyl sugar amounts and quality, they have reduced levels compared to wild ones we do not eat.
“Understanding how they are made is the first step toward breeding cultivated tomatoes, and other plants in this family, to make them more resistant to herbivores.”
Other crops in the Solanaceous family that could benefit from this research include potatoes, peppers, eggplants, and petunias.
In addition, this work shows that the newly discovered gene is active only in one specific cell of one trichome type.
“Not only will we be able to potentially engineer heartier tomatoes, but understanding how to specifically target trichome gene expression without affecting the fruit, we’ll also be able to add other important chemicals for insect resistance and possibly other beneficial traits to the surface of the plants,” Schilmiller says.
The National Science Foundation funded the research.
Source: Michigan State University
“Chocolate can create same high as opium,” reports the Daily Mail. It goes on to
report that his research “found amazing comparisons between obese people and
You’d be forgiven for thinking this was a study in obese people or drug addicts, when in fact the science behind this headline involved rats eating M&Ms chocolates.
The study found that a natural brain chemical called enkephalin – which has a similar effect to opium (the ‘active ingredient’ in heroin) – surged as rats began to eat M&M.
They also found that injecting a synthetic opiate, similar to enkephalin, into a specific area of the brain (the dorsal neostriatum) triggered a feeding frenzy in the rats.
They ate up to 5% of their body weight – the equivalent for an average human would be 3.6 kilos of M&Ms – the same weight in chocolate as three and a half bags of sugar.
The researchers also checked for clues that the rats were ‘enjoying’ their feed (such as licking their lips). They found that the rats did not appear to be enjoying it.
Many people with compulsive eating disorders report that they also take little enjoyment from binge eating, but found it very hard to stop.
The most important question to consider is how applicable this research is likely to be to humans.
While pure speculation at this point, the study raises the possibility that the dorsal neostriatum region of the brain (previously thought just to be associated with physical movement) may also be involved in addiction and compulsive eating.
It may be the case that some people are born with a ‘misfiring’ dorsal neostriatum that triggers a vicious circle of eating, leading to a surge in enkephalin, which leads to more eating, and so on…
However, these speculations are not backed up by this study, a great deal more research will be required to confirm, or disprove, this theory.
The study was carried out by researchers from the University of Michigan and was funded by grants from the US National Institutes of Health.
The study was published in the peer-reviewed scientific journal Current Biology.
The media coverage focused on the link between the reported urge created by enkephalin in rats and what this might mean in humans, specifically obese people and drug addicts. However, the way the Mail’s headline was worded, and the start of the article, would lead many to believe that the research was actually performed on humans, rather than rats. It was only clear that the research was on rats further down in the body of the article.
Similarly, the link between this research and drug addicts was purely speculative, and was not in any way addressed by the rat study itself.
While it may be the case that the dorsal neostriatum region and/or enkephalin may play some sort of role in addictive and compulsive behaviours, this cannot be proved by the evidence provided by this study.
This animal study used rats to investigate the effect of the brain chemical enkephalin on the motivation and urge to consume chocolates, specifically M&Ms.
Enkephalins are part of a category of natural brain chemical, called endorphins, that bind to receptors in the brain called opioid receptors. The opioid receptors are the main route for opiate drugs to exert their effects in the brain, including reducing pain and producing pleasurable feelings.
While used widely in the past as a painkiller, opiates are now usually reserved for the treatment of severe pain due to their potential to cause addiction.
The deeply addictive drug heroin is essentially a type of opiate that has been chemically treated to make it much stronger.
Animal studies are useful in exploring the effects of new chemicals and processes. Rats and other rodents are often used as they share many key anatomical and physiological characteristics with humans. However, the major limitation with this type of work is how applicable the findings will be to humans as the biology of rats and humans, while broadly similar in some areas, can vary significantly in other areas.
The research consisted of a series of three tests.
Firstly, the rats were given free access to M&Ms, which they proceeded to eat for around 20 minutes. During this time both the amount of M&Ms eaten, and the levels of enkephalin inside their brains was measured.
A related chemical called dynorphin was also measured as the researchers wanted to see if this would also be affected by the consumption of chocolate.
The researchers detected a sharp spike in enkephalin levels, which then gradually trailed off as the rats ate their fill.
Secondly, the researchers injected a synthetic version of enkephalin into the dorsal neostriatum areas of the rats’ brains. This sent the rats into a compulsive pattern of eating so severe that the researchers had to remove the rats from the chocolate to stop them eating.
Finally, they performed a similar experiment, but carefully studied the rats to see if they were ‘enjoying’ their eating. There are a number of well-established signs that can show whether a rat is ‘happy’ with its food, such as licking its lips and sticking its tongue out of its mouth.
In the researchers’ opinion, the rats did not seem to be particualry happy during this episode of compulsive eating.
The analysis of the results presented by researchers was broadly appropriate.
When the rats were presented with M&Ms, they consumed approximately 10 M&Ms per 20 minutes (~10g). This caused an immediate peak in the levels of enkephalin in their brains, a 150% rise on their normal levels. Enkephalin levels remained elevated throughout the roughly 20-40 minute period during which each rat continued to eat, and then began to decline as the rats slowed and gradually ceased eating, typically returning back to baseline within the next 40 minutes.
In contrast to enkephalin levels, dynorphin levels failed to increase during eating, and instead remained unchanged throughout the meal.
When the researchers injected enkephalin directly into different areas of the brain to see if it stimulated intense eating habits, they found that the results varied depending on the precise area injected. Sites within the anteromedial quadrant of the dorsal neostriatum produced by far the most intense increases of more than 250%, compared to the normal intake of M&Ms. Most of the rats injected in these sites ate over 17g of M&Ms, equivalent to about 5% of their own body weight, which for rats is a massive amount.
The researchers usefully point out that this degree of elevated consumption (5% of body weight) is roughly proportional to a 68kg human consuming 3.6kg of M&Ms in a single hour, clearly overriding normal satiety signals (satiety is your body’s way of telling you that you have eaten far too much and that it is time to stop).
Being injected in this area also made the rats faster to begin eating, so not only were they being stimulated to ‘eat more’, they were also being stimulated to ‘eat now’.
Further experiments were performed to assess whether the motivation generated by injecting enkephalin was a motivation to eat, or a motivation to seek the taste of sweet rewards. This involved studying the rodent’s faces and tongue protrusions for signals of liking M&Ms versus a sweet solution. These experiments concluded that the injection was making the rats ‘want’ to eat M&Ms more intensely, without making them ‘like; sweetness any more in the sense of the taste.
The authors conclude that their results show that “enkephalin surges” and “stimulation in the same anteromedial dorsal neostriatum region contribute to signalling the opportunity to eat a sensory reward and to causally generating increased consumption of that reward.” Furthermore, that the motivation triggered by this chemical release can more than double the amount of food the rats wanted to eat.
In the final paragraph of the discussion on the implications of their research, the authors of the study mention that this signalling system in rats “could in this way participate in normal motivations and perhaps even in generating intense pathological levels of motivation to over consume reward in binge eating disorders, drug addiction, and related compulsive pursuits”
This study in rats suggests that the action of the brain chemical enkephalin in the specific part of the brain called the anteromedial quadrant of the dorsal neostriatum is vitally important in signalling the desire to consume M&Ms. Additionally, that injecting artificially high levels of this chemical into this specific area of the brain can make the rats eat excessive amounts of M&Ms, in all likelihood overriding the effect of feeling full.
The media and researchers suggest that this chemical and signalling system may be involved in human conditions that generate harmful levels of motivation to over-consume, such as binge eating, drug addiction, and related compulsive pursuits.
However, this was purely speculative and from the researchers’ point of view was put in the context of what their results might mean in the grand scheme of things.
The researchers did not assert this claim with any certainty. The media angle, however, was less reserved, and phrases such as “amazing comparisons between obese people and drug addicts” are misleading and over-state the immediate implications of this research.
This research provides no direct evidence that this enkephalin signalling is involved in these conditions.
How applicable this research is to humans is a crucial first question. While rats are a useful first step in research terms, we cannot assume that the exact effects seen in rats will be replicated if similar experiments were done in humans. Research directly on humans would be the only way to accurately observe the effects.
Arguably it would be unethical to attempt to trigger the binge-eating of huge amounts of chocolate in humans (but it would be more healthy but possible equally unethical, if a way could be found to increase a person’s desire to eat leafy green vegetables or fresh fruit).
With that in mind, a further limitation of the study is that only chocolate, in the form of M&Ms, was studied. The effects of other types of food on enkephalin levels is uncertain.
However, this rat study is a useful first step to investigating the action of enkephalin in mammals.
The slogan for Pringles, “once you pop, you can’t stop,” may be true, and not just because they are delicious. Scientists have found that something in our brains makes us indulge in food as well as drugs and alcohol.
Scientists from the University of Michigan decided to study a part of the brain called the neostriatum that may be involved in providing reward signals when we engage in pleasurable tasks.
The main player in this brain area is enkephalin, a chemical that turns up brain activity. It was discovered in 1975, and is known as a painkiller and a possible neurotransmitter. Enkephalin is produced in the brain and binds to the same receptors as many anesthetic and psychoactive drugs.
To find out how enkephalin acts in the brain, the researchers offered rats an unlimited amount of M&M’s. The average rat ate 10 choclates in 20 minutes, which is a lot of chocolate for their small size. (More on this in the next post).
Researchers found that levels of enkephalin spiked in the neostriatum, and the rats that ate the most M&M’s had the quickest and highest spike of enkephalin.
The spike in enkephalin could have been a result or the cause of the binge eating. To figure this out, the experiment was repeated, but this time the researchers injected the rats’ brains with enkephalin. With the extra brain stimulants, the rats ate twice as much candy — so the chemical seems to be the cause of the overeating, not the result of it.
It could be that the rats overeat because enkephalin makes food taste better. Although it may sound ridiculous, the researchers watched the rats’ facial expressions to see how happy the were during the binge. The more they lick their lips and stick out their tongues, the tastier the food.
But, the dosed rats didn’t show this.
Lead author, Alexandra DiFeliceantonio of the University o Michigan, tells Smithsonian.com’s Surprising Science blog “that the brain has more extensive systems to make individuals want to over-consume rewards than previously thought.”
She concluded: “It may be one reason why over-consumption is a problem today.”
Just remember: Once you pop, try to stop before you eat the entire can.
“Ice cream ‘could be as addictive as cocaine’,” reported the Daily Mail. In a bid to scoop its rivals, the newspaper claimed that new research had whipped up “concerns that the dessert could be genuinely addictive”.
It’s not clear who exactly had these chilling “concerns” over the possible addictive qualities of the frozen snack, but the study in question looked at measures of brain activity in 151 teenagers while they drank an ice cream milkshake. During the scans, teenagers who had frequently eaten ice cream over the past two weeks showed less activity in the “reward areas” of the brain that give pleasurable sensations. This reduced reward sensation was reported to be similar to what is seen in drug addiction as users become desensitised to drugs.
Unsurprisingly, the study did not directly compare brain responses to or cravings for ice cream with those for illegal drugs. Therefore, while some aspects of the brain’s response may be similar, it is not correct to say that this study has found that ice cream is “as addictive” as illegal drugs.
It should be noted that the study included only healthy teenagers of normal weight, and its results may not represent overweight or older people. It also only tested one food, so the results may not apply to other foods.
The study was carried out by researchers from the Oregon Research Institute in the US. Sources of funding were not clear. The study was published in the peer-reviewed American Journal of Clinical Nutrition.
The newspapers focused on the suggestion that ice cream is “as addictive” as drugs. However, it is not possible to conclude this from the study.
This experimental study looked at whether regularly eating ice cream reduces the brain’s pleasurable “reward” response. When we do things that support our survival, such as eating and drinking, the brain gives us a pleasurable reward sensation, reinforcing this behaviour and encouraging it in future. A similar process is also believed to occur in drug addiction, where a person’s reward response to the drug decreases with repeated exposure, leading to a need to take more of the drug.
The researchers reported that people who are obese experience less of a response to food in the reward centres of the brain, which may contribute to over-eating. Repeatedly eating foods with high levels of calories (called “energy dense” foods) has also been shown to lead to brain changes that reduce reward response in rats. The researchers wanted to see if a similar thing happens in humans, by looking at whether regularly eating ice cream reduces the brain’s pleasurable reward response to an ice cream milkshake.
The researchers recruited 151 adolescent volunteers who were not overweight. They asked them how often they ate ice cream, and carried out brain scans while they drank either a tasteless solution or an ice cream milkshake. They then looked at whether the volunteers who ate ice cream frequently showed less brain activity in the reward centres of the brain when drinking the ice cream milkshake.
The study excluded any individuals who were overweight or had reported binge eating in the past three months, as well as any who had used illegal drugs, took certain medications, had a head injury or a mental health diagnosis in the last year. The volunteers completed standard food questionnaires about their eating habits over the past two weeks, including how often they ate ice cream. They also answered questions about food cravings and how much they liked certain foods, including ice cream. The volunteers also had their weight, height and body fat measured.
Volunteers were asked to eat their meals as usual but not to eat anything for five hours before the brain scan. The researchers then gave them either a sip of chocolate ice cream milkshake or a tasteless solution, and monitored the activity in their brain. Each participant received both drinks in a randomised order. The researchers then looked at what happened in the brain during each drink, and whether this varied depending on how much ice cream the volunteer usually ate. They also looked at whether body fat or energy intake from other foods influenced the response.
The researchers found that when the volunteers drank the ice cream milkshake, it activated the parts of the brain involved in giving a pleasurable “reward” feeling. Volunteers who ate ice cream frequently showed less activity in these pleasurable reward areas in response to the milkshake. Percentage of body fat, total energy intake, percentage of energy from fat and sugar, and intake of other energy-dense foods were not related to the level of reward response to the milkshake.
The researchers concluded that their findings show that frequent consumption of ice cream reduces the “reward” response in the brain to eating the food. They reported that a similar process is seen in drug addiction.
The researchers also said that understanding these sorts of processes could help us understand how changes in the brain may contribute to, and help maintain, obesity.
This brain-scanning study suggests that the brain’s pleasurable reward response to ice cream decreases if it is eaten frequently. There are some points to note:
Ice cream ‘could be as addictive as cocaine’, as researchers reveal cravings for the two are similar. Daily Mail, March 5 2012
Ice cream as ‘addictive as drugs’ says new study. The Daily Telegraph, March 5 2012
Burger KS and Stice E. Frequent ice cream consumption is associated with reduced striatal response to receipt of an ice cream–based milkshake. February 15 2012
Analysis by Bazian
“Natural tomatoes are packed with more disease-fighting antioxidants,” the Daily Mail reports, going on to say that “it really may pay off to fork out for the more expensive organic produce”.
This news is based on research comparing the amount of chemicals called polyphenols in organic versus non-organic tomatoes. Polyphenols are produced as tomatoes ripen, and the amount of polyphenols tomatoes produce can be affected by growing conditions. Polyphenols are considered to be antioxidants, and it has been suggested that consuming foods high in antioxidants may be good for your health. The researchers thought that because organic tomatoes ripen for longer as they are grown in less nitrogen-rich soil they would contain higher levels of polyphenols.
When the researchers compared the chemical profile of the two types of tomatoes, they found – as expected – that the organic tomatoes contained higher levels of polyphenols than the non-organic tomatoes.
This study suggests that some organic tomatoes contain higher levels of chemicals called polyphenols than “conventionally grown” tomatoes. It does not, however, tell us whether eating organic tomatoes will provide any additional health benefits over eating conventional tomatoes. Nobody ate the tomatoes, so no health outcomes could be measured.
The study was carried out by researchers from the University of Barcelona and the Institute of Health in Spain. The research was funded by the Spanish Ministry of Science and Innovation, and other Spanish foundations. It is worth noting that Spain is one of the leading producers of tomatoes.
The study was published in the peer-reviewed Journal of Agricultural and Food Chemistry.
The Daily Mail explained the research well. However, the Mail focused on the premise that eating antioxidant-rich foods may be beneficial for health, while not mentioning any of the research that has found contradictory results.
This was a laboratory study. It compared the amount of polyphenol, a type of antioxidant, in organically grown tomatoes to that in “conventionally grown” tomatoes. The researchers report that the amount of polyphenols present in a plant or fruit is affected by growing conditions, including the amount of nutrients in the soil. Polyphenols are produced in plants in part as a response to “stress conditions”, such as a shortage of available nutrients. As conventional farming techniques tend to include the use of pesticides and fertilisers high in nitrogen, the researchers thought that the polyphenol content of the tomatoes would be lower than that seen in organically grown plants, which are grown under more stressful conditions.
There is quite a bit of research into the role of antioxidant-rich foods and human health. Research has looked into their role at fighting heart disease and cancer – with some contradictory results. While this study is related to such research, it can only tell us about the composition of one particular variety of tomato grown in various conditions. It cannot tell us whether higher polyphenol or antioxidant content will be more beneficial to the health of people who eat organic produce.
The researchers purchased raw organic and conventionally grown Daniella tomatoes from markets throughout Barcelona in 2010 and 2011. All of the tomatoes were at a similar stage of ripeness, and were of a similar size. The researchers wanted to examine the properties of raw tomatoes as previous research into their polyphenol content had been done in ketchups and juices.
They then blended the tomatoes to form a paste, and analysed the samples for the presence of several types of polyphenols: flavonols, flavanones, flavones and hydroxycinnamic acids. They then compared the levels of each of these elements between the two types of tomatoes.
The researchers found that organically produced tomatoes contained higher levels of many of the polyphenols. However, the degree of difference in the levels varied across different types of polyphenols. Specifically, the researchers found that:
Overall, the researchers found that the method of production (organic versus conventional) affected the nutrient content of the tomatoes, with organic tomatoes having a higher concentration of polyphenols than conventional tomatoes.
The researchers concluded that production methods affect the nutrient content of raw tomatoes, with organic tomatoes displaying higher concentrations of polyphenols than the conventionally grown tomatoes. They say, “A number of studies have addressed the question of whether agricultural chemicals and other agricultural methods including organic farming affect nutrient content. The question is still unresolved”.
This study suggests that organically grown tomatoes contain higher levels of polyphenols than conventionally grown tomatoes. Whether or not this translates into additional health benefit over non-organic tomatoes is not clear, although the researchers make this assumption in their conclusion.
This study does not tell us whether eating organic tomatoes is more beneficial to our health than eating conventionally grown tomatoes. The researchers say that, based on their findings, “vegetable and fruit products grown in organic agriculture would be expected to be more health-promoting than those produced conventionally”. However, this interpretation does not address the contradictory evidence concerning the health benefits of consuming organic versus non-organic foods, and further studies of how people are affected by their diet would be needed to confirm the interpretation.
Research into antioxidants in food is complicated by the fact that there are many antioxidant and some ‘pro-oxidant’ chemicals found in the same food. Also, more than one antioxidant may be found in a single foodstuff. For example, tomatoes contain both vitamin C and lycopene, which gives red fruit their colour and may also be an antioxidant. Which of the potentially ‘bio-active’ chemicals are important to human health remains uncertain.
Overall, this research tells us more about the effect of farming techniques on a tomato’s nutrient content than it tells us about the effect of a tomato’s nutrient content on our health. However, the field is ripe for someone to conduct controlled trials looking at health outcomes for people.
Links to the headlines
Vallverdú-Queralt A, Jáuregui O, Medina-Remón A, Lamuela-Raventós RM. Evaluation of a Method To Characterize the Phenolic Profile of Organic and Conventional Tomatoes. Journal of Agricultural and Food Chemistry. 2012;60:3373–3380
Recent reviews on polyphenols and human health:
Boehm K, Borrelli F, Ernst E, et al. Green tea (Camellia sinensis) for the prevention of cancer. The Cochrane Collaboration. July 9 2009
Wang L, Lee IM, Zhang SM, et al. Dietary intake of selected flavonols, flavones, and flavonoid-rich foods and risk of cancer in middle-aged and older women. American Journal of Clinical Nutrition 2009;89:905-912.
Analysis by Bazian.
“Eating junk food has a negative effect on mental health, making those who consume it regularly feel depressed,” said The Daily Telegraph.
The news is based on a Spanish study that looked at how 9,000 people’s consumption of fast food and baked goods, such as pies and pastries, related to their risk of depression. In a week when tax on pasties and pies has been the source of great distress for some, researchers found that people who consumed the most fast food and baked good were 37% more likely to become depressed over a six-year period than people with the lowest consumption.
This study had some strengths. For example, it established people’s diets before they were followed to see if they developed depression, which means their diets preceded their depression. However, it cannot conclusively show that fast food directly causes depression. For example, it is just as plausible that diet and depression are both the result of a common factor. Therefore, it’s too early to rebrand the burger and fries as an “unhappy meal”.
This Spanish study was carried out by researchers from the University of Las Palmas in Gran Canaria and the University of Navarra. It was funded by the Spanish Government’s Carlos III Institute of Health.
The study was published in the peer-reviewed journal Public Health Nutrition.
The study’s methods were covered appropriately by the media. However, the 51% increase in risk of depression that was quoted by the Telegraph and Daily Mail did not appear in the research paper. The paper reported an increased risk of 37%.
This prospective cohort study assessed the relationship between eating fast food or processed pastries and developing clinical depression. The research project, called Seguimiento Universidad de Navarra (SUN), is a long-running cohort study that involves university graduates in Spain. The study continuously recruits new participants, and collects data on a variety of factors using mailed questionnaires.
Prospective cohort studies assess participants and then look at the development of various factors over time. They have the advantage of initially measuring the exposure of interest (in this case, consumption of fast foods or processed pastries) in a group of people who do not already have the outcome of interest (in this case, clinical depression). This allows the researchers to be certain that the exposure came before the outcome, which is important for determining a cause-and-effect relationship.
Cohort studies can collect data on a number of other factors that may also account for the relationship between the exposure and outcome. These factors are known as confounders. Adjusting their results to account for the influence of confounders allows researchers to be fairly certain that these confounding factors do not influence the results. However, they cannot take into account factors that weren’t measured during the study. Therefore, it is possible that, during a cohort study, unknown factors may account for the relationship seen, rather than the exposure of interest.
The researchers used data from the SUN study to identify participants for their research. They included people who did not have a clinical diagnosis of depression and who were not taking antidepressant medication (to ensure that the participants were free of depression at the beginning of the study). All participants were also free of cardiovascular disease, diabetes and hypertension.
The participants completed the food frequency questionnaire at the beginning of the study. They assessed two exposure variables: fast food consumption (which included hamburgers, sausages and pizza) and consumption of commercial baked goods (which included muffins, doughnuts, croissants and other baked goods). The researchers then divided the cohort into five groups (quintiles), based on the amount of each food group that they usually consumed.
The participants were then followed up for a median of 6.2 years. The researchers used a mailed questionnaire to determine whether the person had been diagnosed with clinical depression or had been prescribed antidepressant medication during this time.
The researchers collected data on other variables they thought might influence the relationship between eating habits and depression. These included age, sex, body mass index, smoking status, physical activity level, total energy intake and healthy food consumption. They then adjusted for the influence of these variables during the statistical analysis.
In total, 8,964 participants were included in the study. Participants with the highest consumption (quintile 5) of fast food and baked goods were more likely to be single, younger, less active and have worse dietary habits than participants with the lowest consumption (quintile 1).
After a median follow-up of 6.2 years, 493 cases of clinical depression were reported.
When assessing the relationship between fast food consumption and the development of depression, the researchers found:
When assessing the relationship between commercial pastry consumption and the development of depression, the researchers found:
The researchers concluded that their results demonstrate “a positive dose-response relationship between the consumption of fast food and the risk of depression”. In other words, as consumption of fast food increases, so does the risk of depression. They also said that “consumption of commercial baked goods was also positively associated to depressive disorders.”
This study has found an association between consuming high levels of fast food and baked goods and the risk of developing depression. Even though this was a prospective study, it cannot conclusively show that eating lots of hamburgers, sausages and pizza causes depression. The tendency to consume fast food and develop depression may both have stemmed from some common factor, rather than fast food directly causing depression. For example, participants with the highest fast food consumption were generally all single, younger and less active, which may have influenced both their diet and their risk of depression.
Several important factors should be noted:
Overall, this study suggests that there may be an association between eating a lot of fast food or baked goods and developing depression. It is, however, difficult to apply the findings to other groups of people, and it is unclear if the relationship would remain under different conditions.
Fast food ‘gives you the blues’, study finds. The Daily Telegraph, April 2 2012
Junk food is not just bad for your waistline… it can give you the blues too. Daily Mail, April 2 2012
Sánchez-Villegas A, Toledo E, de Irala J et al. Fast-food and commercial baked goods consumption and the risk of depression. Public Health Nutrition, March 2012, 15: pp 424-432
Google is known for its data and how it optimizes its community – but did you know that they also optimize their own employees? Using their internal “People Analytics” program, Google looks at how their employees eat in their free cafeteria and optimizes it so they’re healthier, make better eating decisions, and are more productive through that process. Google does this by “nudging” their employees into making the correct eating decisions daily. Through these lessons, we can also learn more about our own decision making process and how we might improve our eating habits by “optimizing” for better decision making.