$9 brocoli. $11 milk, you get the point. Technology is awesome when used properly. Imagine having such a system in place in all cities experiencing poverty.
$9 brocoli. $11 milk, you get the point. Technology is awesome when used properly. Imagine having such a system in place in all cities experiencing poverty.
According to Professor Julia Rucklidge of the University of Canterbury, New Zealand, poor modern diets could be playing a surprisingly big role in the epidemic. In her research, she has uncovered a number of longitudinal and association studies illustrating the significant impact that diet can have on mental health.
One of the studies she cites is the SUN Project study, which is one of the biggest studies so far to explore the connection between depression and food. The study followed 12,000 participants over the course of six years. None had depression at the start of the study; 657 people had the condition by the study’s close. That study concluded that depression was related to the intake of trans unsaturated fatty acids.
Trans fats have been getting a lot of negative press lately because of their serious adverse health effects. Created when hydrogen is added to liquid vegetable oils to solidify them, it’s used in lots of fast foods and other processed foods. These fats have been everywhere you look in Western grocery stores in recent years, from baked goods and cookies to margarine, donuts, crackers and frozen pizza.
The substances are dangerous for human health in many ways, causing inflammation, obesity, insulin resistance, irrational behavior, and aggression. Dr. Beatrice Golumb, the lead author of a study that linked trans fats to poor memory function in men younger than 45, said: “As I tell patients, while trans fats increase the shelf life of foods, they reduce the shelf life of people.”
An FDA ban on trans fats finally takes effect this year, but the damage to countless Americans has already been done. While natural fats like omega 3 essential fatty acids are actually good for brain health, trans fats destroy brain cells, impact hormone production, and increase inflammation in the brain. They also reduce serotonin production, which is why they cause depression and memory problems.
Antidepressants are so commonplace these days that lots of people take them without giving the matter a second thought. While the drug companies sit back and rake in the profits, however, those taking these medications are suffering. Some of the most common side effects reported in a New Zealand study included sexual problems, a feeling of emotional numbness, apathy, and suicidal thoughts.
It’s the latter that’s the scariest side effect of all, with one study showing that antidepressants double a person’s likelihood of becoming violent and suicidal. The effect is particularly dramatic in young people, prompting the FDA to order all antidepressants to carry a “black box warning” informing people of the increased suicidal symptoms risk. With more than ten percent of Americans taking these drugs, it’s not surprising that we’re seeing so many incidents of mass violence like school shootings.
The physical side effects of antidepressants are also serious. They increase your risk of heart disease, breast cancer, and Type 2 diabetes, to name just a few.
The good news is that there are lots of safe ways you can feel better. Everyone’s experience with depression will be different and not all methods work for all cases, but some people have found success with yoga, meditation, regular exercise, and a clean diet heavy in superfoods. Given the connection between trans fats and depression, however, cutting out foods that contain these toxic ingredients should be everyone’s top priority.
Sources for this article include:
Sadly, today’s corporate textbook-producers are no more interested in feeding student curiosity about the poverty and inequality that drove the famine than were British landlords interested in feeding Irish peasants
“Wear green on St. Patrick’s Day or get pinched.” That pretty much sums up the Irish-American “curriculum” that I learned when I was in school. Yes, I recall a nod to the so-called Potato Famine, but it was mentioned only in passing.
Sadly, today’s high school textbooks continue to largely ignore the famine, despite the fact that it was responsible for unimaginable suffering and the deaths of more than a million Irish peasants, and that it triggered the greatest wave of Irish immigration in U.S. history. Nor do textbooks make any attempt to help students link famines past and present.
Yet there is no shortage of material that can bring these dramatic events to life in the classroom. In my own high school social studies classes, I begin with Sinead O’Connor’s haunting rendition of “Skibbereen,” which includes the verse:
… Oh it’s well I do remember, that bleak
The landlord and the sheriff came, to drive
Us all away
They set my roof on fire, with their cursed
And that’s another reason why I left old
By contrast, Holt McDougal’s U.S. history textbook The Americans, devotes a flat two sentences to “The Great Potato Famine.” Prentice Hall’s America: Pathways to the Present fails to offer a single quote from the time. The text calls the famine a “horrible disaster,” as if it were a natural calamity like an earthquake. And in an awful single paragraph, Houghton Mifflin’s The Enduring Vision: A History of the American People blames the “ravages of famine” simply on “a blight,” and the only contemporaneous quote comes, inappropriately, from a landlord, who describes the surviving tenants as “famished and ghastly skeletons.” Uniformly, social studies textbooks fail to allow the Irish to speak for themselves, to narrate their own horror.
These timid slivers of knowledge not only deprive students of rich lessons in Irish-American history, they exemplify much of what is wrong with today’s curricular reliance on corporate-produced textbooks.
First, does anyone really think that students will remember anything from the books’ dull and lifeless paragraphs? Today’s textbooks contain no stories of actual people. We meet no one, learn nothing of anyone’s life, encounter no injustice, no resistance. This is a curriculum bound for boredom. As someone who spent almost 30 years teaching high school social studies, I can testify that students will be unlikely to seek to learn more about events so emptied of drama, emotion, and humanity.
Nor do these texts raise any critical questions for students to consider. For example, it’s important for students to learn that the crop failure in Ireland affected only the potato — during the worst famine years, other food production was robust. Michael Pollan notes in The Botany of Desire, “Ireland’s was surely the biggest experiment in monoculture ever attempted and surely the most convincing proof of its folly.” But if only this one variety of potato, the Lumper, failed, and other crops thrived, why did people starve?
Thomas Gallagher points out in Paddy’s Lament, that during the first winter of famine, 1846-47, as perhaps 400,000 Irish peasants starved, landlords exported 17 million pounds sterling worth of grain, cattle, pigs, flour, eggs, and poultry — food that could have prevented those deaths. Throughout the famine, as Gallagher notes, there was an abundance of food produced in Ireland, yet the landlords exported it to markets abroad.
The school curriculum could and should ask students to reflect on the contradiction of starvation amidst plenty, on the ethics of food exports amidst famine. And it should ask why these patterns persist into our own time.
More than a century and a half after the “Great Famine,” we live with similar, perhaps even more glaring contradictions. Raj Patel opens his book, Stuffed and Starved: Markets, Power and the Hidden Battle for the World’s Food System: “Today, when we produce more food than ever before, more than one in ten people on Earth are hungry. The hunger of 800 million happens at the same time as another historical first: that they are outnumbered by the one billion people on this planet who are overweight.”
Patel’s book sets out to account for “the rot at the core of the modern food system.” This is a curricular journey that our students should also be on — reflecting on patterns of poverty, power, and inequality that stretch from 19th century Ireland to 21st century Africa, India, Appalachia, and Oakland; that explore what happens when food and land are regarded purely as commodities in a global system of profit.
But today’s corporate textbook-producers are no more interested in feeding student curiosity about this inequality than were British landlords interested in feeding Irish peasants. Take Pearson, the global publishing giant. At its website, the corporation announces (redundantly) that “we measure our progress against three key measures: earnings, cash and return on invested capital.” The Pearson empire had 2017 worldwide profits of $801 million. Multinationals like Pearson have no interest in promoting critical thinking about an economic system whose profit-first premises they embrace with gusto.
As mentioned, there is no absence of teaching materials on the Irish famine that can touch head and heart. In a role play, “Hunger on Trial,” that I wrote and taught to my own students in Portland, Oregon — included at the Zinn Education Project website — students investigate who or what was responsible for the famine. The British landlords, who demanded rent from the starving poor and exported other food crops? The British government, which allowed these food exports and offered scant aid to Irish peasants? The Anglican Church, which failed to denounce selfish landlords or to act on behalf of the poor? The economic system, which sacrificed Irish peasants to the logic of colonialism and the capitalist market?
These are rich and troubling ethical questions. They are exactly the kind of issues that fire students to life and allow them to see that history is not simply a chronology of dead facts stretching through time.
So go ahead: Have a Guinness, wear a bit of green, and put on the Chieftains. But let’s honor the Irish with our curiosity. Let’s make sure that our schools show some respect, by studying the social forces that starved and uprooted over a million Irish — and that are starving and uprooting people today.
Note: This piece, which originally appeared on the Zinn Education Project website here, is an updated version of a piece that ZEP and Common Dreams have run in years past.
© 2018 Zinn Education Project (Coordinated by Rethinking Schools and Teaching for Change)
Published on Feb 8, 2018
March 16, 2018
By Dr. Mercola
According to the World Health Organization, depression is now the leading cause of ill health and disability worldwide,1,2 affecting an estimated 322 million people globally, including more than 16 million Americans, 6 million of which are seniors.3 Statistics also reveal we’re not being particularly effective when it comes to prevention and treatment. Worldwide, rates of depression increased by 18 percent between 2005 and 2015.4
If you or someone you love is struggling with depression or some other mental health problem, remember that your diet is a foundational aspect that must not be overlooked. As noted in a 2015 study5 published in the medical journal Lancet:
“Although the determinants of mental health are complex, the emerging and compelling evidence for nutrition as a crucial factor in the high prevalence and incidence of mental disorders, suggests that diet is as important to psychiatry as it is to cardiology, endocrinology and gastroenterology.”
Recent research6,7,8 looking at the effects of the antihypertensive DASH diet on mental health concluded this kind of dietary pattern, which is low in sugar and high in fresh fruits and vegetables, can help reduce the risk of depression in seniors. Overall, people who followed the DASH diet were 11 percent less likely to develop depression over the following six years, whereas those following a standard Western diet, high in red meat and low in fruits and vegetables, had the highest rates of depression.
It’s worth noting that while many conventional experts recommend the DASH diet, it is not necessarily ideal for optimal health, as it also promotes whole grains and low-fat foods, including low-fat dairy. Healthy fats, including saturated animal and plant fats and animal-based omega-3, are quite crucial for optimal brain health. I believe the reason the DASH diet produces many beneficial results is because it is low in sugar and high in unprocessed foods — not because it’s low in fat.
Other studies have shown that unprocessed foods, especially fermented foods, help optimize your gut microbiome, thereby supporting optimal mental health,9,10 whereas sugar, wheat (gluten) and processed foods have been linked to a greater risk for depression, anxiety and even suicide. The primary information highway between your gut and your brain is your vagus nerve, which connects the two organs.11
Your gut also communicates to your brain via the endocrine system in the stress pathway (the hypothalamus, pituitary and adrenal axis), and by producing mood-boosting neurotransmitters like serotonin, dopamine and gamma-aminobutyric acid or GABA. These communication links help explain why your gut health has such a significant impact on your mental health.
A number of food ingredients can cause or aggravate depression, but one of the most significant is sugar, particularly refined sugar and processed fructose.12 For example, in one study, men consuming more than 67 grams of sugar per day were 23 percent more likely to develop anxiety or depression over the course of five years compared to those whose sugar consumption was less than 40 grams per day (which is still far higher than the 25 grams per day recommended for optimal health).13
This held true even after accounting for other contributing factors, such as socioeconomic status, exercise, alcohol use, smoking, other eating habits, body weight and general physical health. Lead author Anika Knüppel,14 a research student in the department of epidemiology and public health at University College London, commented on the findings, saying:15
“Sweet food has been found to induce positive feelings in the short-term. People experiencing low mood may eat sugary foods in the hope of alleviating negative feelings. Our study suggests a high intake of sugary foods is more likely to have the opposite effect on mental health in the long-term.”
Research16 published in 2002, which correlated per capita consumption of sugar with prevalence of major depression in six countries, also found “a highly significant correlation between sugar consumption and the annual rate of depression.” A Spanish study17 published in 2011 linked depression specifically to consumption of baked goods.
Those who ate the most baked goods had a 38 percent higher risk of depression than those who ate the least. This makes sense when you consider baked goods contain both processed grains and added sugars.
Sugar has been shown to trigger depression and other mental health problems through a number of different mechanisms, including the following:
|Feeding pathogens in your gut, allowing them to overtake more beneficial bacteria.|
|Suppressing activity of a key growth hormone in your brain called brain-derived neurotrophic factor (BDNF). BDNF levels are critically low in both depression and schizophrenia, and animal models suggest this may actually be a causative factor.|
|Triggering a cascade of chemical reactions in your body that promote chronic inflammation, which over the long term disrupts the normal functioning of your immune system and wreaks havoc on your brain.|
|Contributing to insulin and leptin resistance, which also plays a significant role in your mental health.|
|Affecting dopamine, a neurotransmitter that fuels your brain’s reward system18 (hence sugar’s addictive potential19,20,21) and is known to play a role in mood disorders.22|
|Damaging your mitochondria, which can have bodywide effects. Your mitochondria generate the vast majority of the energy (adenosine triphosphate or ATP) in your body.When sugar is your primary fuel, excessive reactive oxygen species (ROS) and secondary free radicals are created, which damage cellular mitochondrial membranes and DNA. As your mitochondria are damaged, the energy currency in your body declines and your brain will struggle to work properly.
Healthy dietary fats, on the other hand, create far fewer ROS and free radicals. Fats are also critical for the health of cellular membranes and many other biological functions, including and especially the functioning of your brain.
Among the most important fats for brain function and mental health are the long-chained animal-based omega-3 fats DHA and EPA. Not only are they anti-inflammatory, but DHA is actually a component in every cell of your body, and 90 percent of the omega-3 fat found in brain tissue is DHA.
A paper23 published in Nutritional Neuroscience last year looked at evidence from laboratory, population research and clinical trials to create “a set of practical dietary recommendations for the prevention of depression, based on the best available current evidence.” According to this paper, the published evidence reveals five key dietary recommendations for the prevention of depression:
Three brain- and mood-wrecking culprits you’ll automatically avoid when avoiding processed foods are added sugars, artificial sweeteners24 and processed vegetable oils — harmful fats known to clog your arteries and cause mitochondrial dysfunction. Gluten also appears to be particularly problematic for many. If you’re struggling with depression or anxiety, you’d be well-advised to experiment with a gluten-free diet.
Certain types of lectins, especially wheat germ agglutinin (WGA), are also known for their psychiatric side effects. WGA can cross your blood brain barrier25 through a process called “adsorptive endocytosis,” pulling other substances with it. WGA may attach to your myelin sheath26 and is capable of inhibiting nerve growth factor,27 which is important for the growth, maintenance and survival of certain target neurons.
Processed foods are also a significant source of genetically engineered (GE) ingredients and toxic herbicides like Roundup. In addition to being toxic and potentially carcinogenic, glyphosate, the active ingredient in Roundup, has been shown to preferentially decimate beneficial gut microbes. Many grains need to dry in the field before being harvested, and to speed that process, the fields are doused with glyphosate a couple of weeks before harvest.
As a result of this practice, called desiccation, grain-based products tend to contain rather substantial amounts of glyphosate. This reason alone is enough to warrant a grain-free diet, but if you do choose to eat whole grain products, make sure it’s organic to avoid glyphosate contamination.
Your beverage choices may also need an overhaul, as most people drink very little pure water, relying on sugary beverages like sodas, fruit juices, sports drinks, energy drinks and flavored water for their hydration needs. None of those alternatives will do your mental health any favors.
As mentioned above, one of the mechanisms by which good nutrition bolsters mental health is by cutting down inflammation in your body, and a high-sugar diet is exceptionally inflammatory. A number of studies have linked depression with chronic inflammation.28,29
For example, a study30 published in the Journal of Clinical Psychiatry in 2016 concluded that depressed patients had 46 percent higher levels of the inflammatory marker C-reactive protein in their blood. Interestingly, they also had 16 percent lower levels of low fractional exhaled nitric oxide, which adds further support for doing exercises that boost nitric oxide cycling, such as the Nitric Oxide Dump exercise. As explained in the study:
“Nitric oxide (NO), in addition to being an inflammatory mediator, is also a neurotransmitter at the neuron synapses. It modulates norepinephrine, serotonin, dopamine and glutamate and thus is speculated to play a role in the pathogenesis of depression. Nitric oxide is also currently seen as a marker of airway inflammation and can be measured during exhalation.
Fractional exhaled nitric oxide (FeNO) may represent both constitutive and inducible NO. Small studies suggest that subjects with depressed mood have low levels of FeNO … Subjects with depression also have low levels of plasma and platelet NO. The low systemic levels of NO have been postulated to be responsible for the increased risk of cardiovascular events observed in subjects with depression, as NO produces vasodilatation …
In summary, this large population-based study found that depression is associated with high levels of CRP and low levels of FeNO. These findings corroborate the premise that inflammation could play a role in the pathophysiology of major depression and that major depression may be seen as a psychoneuroimmunological disorder.”
In addition to transitioning from a diet of processed fare to real food, consider:
• Implementing a cyclical ketogenic diet, high in healthy fats, low in net carbs with moderate amounts of protein. This kind of diet will optimize your mitochondrial function, which has significant implications for mental health. In fact, one noticeable effect of nutritional ketosis is mental clarity and a sense of calm. The reason for this welcome side effect has to do with the fact that when your body is able to burn fat for fuel, ketones are created, which is the preferred fuel for your brain.
• Intermittent fasting will also help optimize your brain function and prevent neurological problems by activating your body’s fat-burning mode, preventing insulin resistance and reducing oxidative stress and inflammation, the latter of which has been identified as a causative factor in depression.31,32
While you may achieve some of the benefits from intermittent fasting simply by respecting the time boundaries, regardless of the foods you consume, it is far better if you consume high-quality unprocessed food.
Since you’ll be eating less, it’s vitally important that you get proper nutrition. Healthy fats are essential because intermittent fasting pushes your body to switch over to fat-burning mode. Particularly if you begin to feel tired and sluggish, it may be a sign that you need to increase the amount of healthy fat in your diet.
• Water fasting. Once you’re starting to burn fat for fuel, gradually increase the length of your daily intermittent fasting to 20 hours per day. After a month of 20-hour daily fasting, you’re likely in good metabolic shape and able to burn fat as fuel. At that point, you can try a four or five-day water-only fast.
I now do a quarterly five-day fast, as I believe this is one of the most powerful metabolic health interventions out there. A five-day fast will effectively clean out senescent cells that have stopped duplicating due to aging or oxidative damage, which would otherwise clog up your optimal biologic function by causing and increasing inflammation.
• Exercise and get regular movement throughout your day. Exercise is one of the most effective antidepressant strategies out there, beating most medical interventions for depression.
Another foundational strategy to prevent or treat depression and anxiety is to limit exposure to electromagnetic fields (EMFs). Studies have linked excessive EMF exposure to an increased risk of both depression and suicide.33 Addiction to or “high engagement” with mobile devices can also trigger depression and anxiety, according to recent research from the University of Illinois.34
Research35 by Martin Pall, Ph.D., reveals a previously unknown mechanism of biological harm from microwaves emitted by cellphones and other wireless technologies, which helps explain why these technologies can have such a potent impact on your mental health. Embedded in your cell membranes are voltage gated calcium channels (VGCCs), which are activated by microwaves. When activated, a cascade of biochemical effects occurs that result in the creation of extremely destructive hydroxyl free radicals.
Hydroxyl free radicals decimate mitochondrial and nuclear DNA, their membranes and proteins. The end result is mitochondrial dysfunction, which we now know is at the heart of most chronic disease. The tissues with the highest density of VGCCs are your brain, the pacemaker in your heart and male testes. Hence, health problems such as Alzheimer’s, anxiety, depression, autism, cardiac arrhythmias and infertility can be directly linked to excessive microwave exposure.
So, if you struggle with anxiety or depression, be sure to limit your exposure to wireless technologies, in addition to addressing your diet and exercise. Simple measures include turning your Wi-Fi off at night, not carrying your cellphone on your body and not keeping portable phones, cellphones and other electric devices in your bedroom. The electric wiring inside your bedroom walls is probably the most important source to address.
Your best bet here is to turn off the power to your bedroom at night. This will work if there are no adjacent rooms. If there are, you may need to shut those rooms off also. The only way to know would be to measure the electric fields. For additional lifestyle guidelines that can help prevent and/or treat depression, see the nondrug solutions section at the end of this previous article on depression.
“There are several contenders for best diet for your heart, but two of the leading options are the lacto-ovo-vegetarian diet (excludes meat and fish but includes eggs and dairy) and the Mediterranean diet (rich in vegetables, fruit, wholegrains, fish and poultry, and includes red wine and some red meat).”
by: Tracey Watson
March 15, 2018
Heart disease claims more American lives than any other disease. A quarter of all deaths in our country are caused by heart disease. Close to 800,000 people have a first heart attack each year, and it kills over half a million people annually.
There are many theories about how best to prevent coronary conditions, but it is generally understood that there is a clear link between obesity and heart disease, and the best way to prevent it is to maintain a healthy weight.
This naturally leads to the question of how best to accomplish this goal. There are several contenders for best diet for your heart, but two of the leading options are the lacto-ovo-vegetarian diet (excludes meat and fish but includes eggs and dairy) and the Mediterranean diet (rich in vegetables, fruit, wholegrains, fish and poultry, and includes red wine and some red meat).
As reported by Science Daily, a recent study by researchers from the University of Florence and Careggi University Hospital in Italy has made the surprising discovery that both these diets effectively reduce risk factors for cardiovascular disease. The study was published in Circulation, the journal of the American Heart Association.
The study included 107 volunteers aged between 18 and 75 who were all overweight but otherwise healthy. Half the participants were assigned to follow a lacto-ovo-vegetarian diet, while the other half followed the Mediterranean way of eating. After three months, the volunteers were asked to switch to the opposite eating plan for a further three months. (Related: Vegetarian diets found to be the most effective way to lose weight, reveals new study.)
Irrespective of which diet they followed, the participants all lost around 3 pounds of body fat and 4 pounds of overall weight. Their body mass indexes (BMIs) also changed by about the same amount.
There were other fundamental differences between the volunteers’ results, however. Those who followed the vegetarian diet were more successful at lowering their LDL, or “bad” cholesterol levels, while those who had followed the Mediterranean diet experienced greater reductions in triglyceride levels. Triglycerides are a type of fat lipid in the blood, and elevated levels are an indicator of an increased risk of heart disease.
“The take-home message of our study is that a low-calorie lacto-ovo-vegetarian diet can help patients reduce cardiovascular risk about the same as a low-calorie Mediterranean diet,” said Francesco Sofi, the study’s lead author. “People have more than one choice for a heart-healthy diet.” (Related: Mediterranean diet, olive oil and nuts improve brain health, memory and thinking ability.)
Cheryl A. M. Anderson, an associate professor of preventive medicine at the University of California, San Diego, who was not involved in the study but who wrote an editorial accompanying it, noted that one possible reason for the similarity in results between the two eating plans is that both include a rich variety of fruits, vegetables, wholegrains, nuts and legumes. Both plans also limit saturated fats and are rich in an array of nutrients. (Related: Discover the myriad benefits of good food at Nutrients.news.)
The study results are limited, however, in that none of the participants was at high risk of heart disease at the time the study was conducted. Anderson noted that further studies would need to be undertaken to evaluate whether patients at higher risk of cardiovascular disease would also benefit in a similar way to following one of these eating plans. She also noted that further investigation should be undertaken to see whether other diets, including those that “emphasize fresh foods and limit sugars, saturated fats, and sodium can prevent and manage obesity and cardiovascular diseases” just as effectively.
Sources for this article include:
You aren’t what you eat, exactly. But over many generations, what we eat does shape our evolutionary path. “Diet,” says anthropologist John Hawks, of the University of Wisconsin-Madison, “has been a fundamental story throughout our evolutionary history. Over the last million years there have been changes in human anatomy, teeth and the skull, that we think are probably related to changes in diet.”
As our evolution continues, the crucial role of diet hasn’t gone away. Genetic studies show that humans are still evolving, with evidence of natural selection pressures on genes impacting everything from Alzheimer’s disease to skin color to menstruation age. And what we eat today will influence the direction we will take tomorrow.
When mammals are young, they produce an enzyme called lactase to help digest the sugary lactose found in their mothers’ milk. But once most mammals come of age, milk disappears from the menu. That means enzymes to digest it are no longer needed, so adult mammals typically stop producing them.
Thanks to recent evolution, however, some humans defy this trend.
Around two-thirds of adult humans are lactose intolerant or have reduced lactose tolerance after infancy. But tolerance varies dramatically depending on geography. Among some East Asian communities, intolerance can reach 90 percent; people of West African, Arab, Greek, Jewish and Italian descent are also especially prone to lactose intolerance.
Northern Europeans, on the other hand, seem to love their lactose—95 percent of them are tolerant, meaning they continue to produce lactase as adults. And those numbers are increasing. “In at least different five cases, populations have tweaked the gene responsible for digesting that sugar so that it remains active in adults,” Hawks says, noting it is most common among peoples in Europe, the Middle East and East Africa.
Ancient DNA shows how recent this adult lactose tolerance is, in evolutionary terms. Twenty-thousand years ago, it was non-existent. Today, about one-third of all adults have tolerance.
That lightning-fast evolutionary change suggests that direct milk consumption must have provided a serious survival advantage over peoples who had to ferment dairy into yogurt or cheese. During fermentation, bacteria break down milk sugars including lactase, turning them into acids and easing digestion for those with lactose intolerance. Gone with those sugars, however, is a good chunk of the food’s caloric content.
Hawks explains why being able to digest milk would have been such a boon in the past: “You’re in a nutrition limited environment, except you have cattle, or sheep, or goats, or camels, and that gives you access to a high energy food that infants can digest but adults can’t,” he says. “What it does is allow people to get 30 percent more calories out of milk, and you don’t have the digestive issues that come from milk consumption.”
A recent genetic study found that adult lactose tolerance was less common in Roman Britain than today, meaning its evolution has continued throughout Europe’s recorded history.
These days, many humans have access to plentiful alternative foods as well as lactose-free milk or lactase pills that help them digest regular dairy. In other words, we can circumvent some impacts of natural selection. That means traits like lactose tolerance might not have the same direct impacts on survival or reproduction that they once did—at least in some parts of the world.
“As far as we know, it makes no difference to your survival and reproduction in Sweden if you can digest milk or not. If you’re eating out of a supermarket (your dairy tolerance doesn’t affect your survival). But it still makes a difference in East Africa,” Hawks says.
These days, it isn’t uncommon to find an entire grocery store aisle devoted to gluten-free cookies, bread and crackers. Yet trouble digesting gluten—the main protein found in wheat—is another relatively recent snag in human evolution. Humans didn’t start storing and eating grains regularly until around 20,000 years ago, and wheat domestication didn’t begin in earnest until about 10,000 years ago.