For decades we have been told what to eat and what not to eat. And the problem is, much of this advice changes constantly, sometimes even to the opposite extreme! Wasn’t it just a few years ago that we were consuming whole milk by the glass to “build strong bones?”
One would hope that science is behind all of the guidelines out there but unfortunately, that’s not always the case and even when it is, nutritional research is often hard to get right. Because of the overwhelming number of variables that determine health, it is particularly challenging to isolate the effects of a specific type of food on our wellbeing.
It also doesn’t help that many of the “official” dietary recommendations that come from national institutions receive funding from the food industry itself, which may, at times, result in biased advice. So, I think it’s fair to say that knowing what to eat and who to trust on what to eat can feel like a huge undertaking.
Instead of being unsure because of contradicting information or influenced by savvy marketing, let’s go through some of the most common nutritional advice, analyze its related research, and decide for ourselves if these guidelines are true, false, or somewhere in between.
A gluten-free diet is a healthier diet: It depends
Firstly, what is gluten? The term gluten refers to a group of proteins, known as prolamins, that are found in many grains such as wheat, barley and rye. Given the widespread trend of avoiding gluten, it may surprise you to know that gluten-related diseases, such as celiac, are extremely rare affecting less than one percent of the US population (Niland et al., 2018).
Celiac is an auto-immune disease in which the body mistakenly recognizes gluten as something that needs to be defended against. When not following a gluten-free diet, patients with celiac may experience a range of other health problems ranging from IBS to neurological conditions like depression or anxiety. Additionally, a less extreme form of gluten intolerance, referred to as non celiac gluten sensitivity (NCGS), exists more commonly amongst populations and often causes symptoms of fatigue, headaches, or joint pain.
That said, as gluten-free becomes trendier by the day, more and more people without any form of a diagnosed gluten intolerance choose to avoid gluten. Is there sound evidence behind this?
Mark Hyman, functional medicine doctor and author, would likely say yes, suggesting that “the most advanced research on the subject has concluded that nobody - not one of us - can properly process gluten” (Hyman, 93). Particularly holistic wellness professionals, like Hyman, believe that even though symptoms may not be physically or obviously apparent, there is a chance that gluten consumption may still cause damage in the body.
Hyman explains how gluten may be harmful and refers to a study conducted by the University of Maryland. This study focuses on zonulin, a protein that our bodies produce in response to eating gluten. This protein contributes to leaky gut, as it loosens the connections between cells in the intestine which results in microbes seeping through these cells into the bloodstream which leads to inflammation and disease (Hyman, 194). Therefore, following a gluten-free diet theoretically protects against this physical damage.
Now, it’s important to understand why many other professionals caution against avoiding gluten entirely when not diagnosed with a gluten intolerance. The rationale behind this thought is often that a gluten-free diet can be lower in fiber, result in nutritional deficiencies (such as in B vitamins, iron, and trace minerals), and can be very expensive. In fact, one study from 2015 found that gluten-free bakery products were approximately 267% more expensive than the gluten-containing alternatives (Leonard et al., 2017).
Unfortunately, just because something is labeled “gluten-free,” does not automatically give us the green light. In fact, for any product that is attempting to closely mimic the non gluten-free option, it’s worth taking a closer look at the ingredients. For example, many gluten-free breads contain all sorts of gums, are low in dietary fiber, and are high in sugar to compensate for the lack of gluten. Unfortunately, these types of ingredients likely neutralize any potential benefit from there being no gluten in the product. Here’s a rule of thumb when shopping for gluten-free alternatives: if you don’t recognize the ingredients, put it back on the shelf.
Unless you’re willing and able to spend high amounts of money for clean gluten-free baked goods with nutritious ingredients, it’s typically best to steer clear of manufactured gluten-free alternatives. Sticking to naturally gluten-free, whole, unprocessed foods such as quinoa or rice is almost always going to be a healthier option than store-bought gluten-free processed products.
Overall, avoiding gluten can certainly be beneficial but it is important to ensure that you are still meeting all of your recommended daily nutrient requirements.
Avoid egg yolks because they raise cholesterol: Mostly False
Isn’t that exciting? Beyond their satisfying taste, eggs are one of the most nutritious foods out there - loaded with all of the nutrients required to create life!
And while the egg white is certainly rich in protein, the yolk is actually the most nutritious part of the egg. In fact, the egg yolk contains a vast range of vitamins, such as B12 and all of those that are fat-soluble (A, D, E, K). Additionally, the yolks contain many essential minerals, such as calcium, magnesium and potassium, along with lutein and zeaxanthin, carotenoids which promote eye health.
So, why then have yolks taken on such a bad reputation? Well, the concerns regarding consuming egg yolks can largely be attributed to the misguided belief that high levels of dietary cholesterol raise blood cholesterol. An article from Harvard Health points out the invalidity of this idea, however, revealing that the majority of cholesterol present in our bodies comes from the liver and not the cholesterol that we consume (Harvard Health, 2019).
This article also importantly addresses the fact that the liver produces cholesterol mostly due to high levels of certain saturated and trans fats in the foods we eat. Eggs contain relatively small amounts of these fats and therefore would contribute little to cholesterol production. This suggests that what we should really be concerned about when eating eggs is not the egg itself but what we eat with it. For example, if you typically serve your eggs with a buttered English muffin or a side of pancakes, you might want to start substituting those foods for a side salad or a healthier bread alternative to protect cholesterol levels.
Consuming a moderate amount of eggs (around one a day) is perfectly healthy and not linked to an increased risk of cardiovascular disease. The only caveat is in the case of diabetic individuals or people prone to poor cholesterol levels, hence the “mostly false” label.
It’s best to avoid refined-sugar: True
Though most of us have probably been conditioned since childhood to somewhat avoid sugar, the average adult has approximately 24 teaspoons of added sugar per day. That’s 384 calories of sugar alone (Harvard Health, 2019). And I wish I could tell you that this is completely healthy but science says otherwise.
Significant research has shown that an excessive intake of refined-sugar is linked to numerous health problems, including obesity, diabetes, high blood pressure, and heart disease. An article from Harvard Health Publishing points out that one of the main sources of sugar for many people is sugary beverages. These drinks are particularly problematic as they disrupt the body’s natural ability to control appetite, given that liquid calories do not provide the same satisfaction as do calories from foods. Therefore, in the case of sugar-filled drinks, not only is the drink itself unhealthy, but so are the overeating habits that accompany it.
Additionally, high amounts of added sugar consumption are associated with increased chronic inflammation in the body. One research review from 2018 shows that several studies have affirmed the link between diets high in added sugar and chronic inflammation. From these studies, it appears that sugar-filled diets cause higher levels of inflammatory markers in blood, such as C-reactive protein (Della Corte et al., 2018).
The overall effects of sugar on wellbeing make it particularly detrimental for cardiovascular health. In one study from 2014, it was found that there is a connection between a high-sugar diet and an increased risk of heart disease. The study was conducted over 15 years and the results showed that participants who had a sugar intake making up around 20 percent of their calories had around a 40 percent higher risk of dying from heart disease (Harvard Health, 2019).
With the association of added sugar with all of these health concerns, we should really be thinking about cutting down our sugar intake.
Cow’s milk is healthy and builds strong bones: False
I’m sure that growing up many of us were encouraged to drink milk every day. For quite some time, many people were convinced that milk was essential for strong healthy bones because of its calcium content. And this isn’t an unreasonable idea, given the fact that milk is critical for the growth of infants and baby animals. Modern research, however, has shown that this belief is not grounded in science.
In fact, various studies show that consuming milk can have the opposite effect on our bodies, weakening our bones. For example, one study involving around 100,000 people found that men who drank large quantities of milk as teenagers were more likely to experience bone fractures as adults. The results of this study show that each additional glass consumed per day is associated with a 9% increased risk of fractures (Feskanich et al., 2013). Another study focused on adolescent females similarly highlights the counter productive effect of drinking milk on bone health, as it found that girls who consumed the most dairy were most susceptible to stress fractures (Sonneville et al., 2012).
Another problematic aspect of milk is its high content of growth hormones. While these hormones are beneficial for the development of calves, research shows their detriment to humans. In fact, these growth hormones have been linked to causing various cancers in humans. One recent press release reported that depending on the amount, milk consumption can increase a woman’s risk of breast cancer up to 80% (Science Daily, 2020). Other studies have suggested the association of drinking milk with other cancers as well such as prostate and ovarian.
Another convincing argument for avoiding cow’s milk is the high prevalence of lactose intolerance. A review from 2015 approximates that 65 to 70 percent of the entire world’s population experiences lactose intolerance in some capacity (Bayless, 2017). This type of intolerance often results in uncomfortable symptoms such as bloating and cramping. Overall, the takeaway here seems to be that cow milk is best reserved for baby cows.
Eating before bed is unhealthy: It depends
For the most part, nighttime eating has been painted in a negative light. However, as it turns out, whether or not eating before bed is actually unhealthy for you depends on a few different factors including the type of food eaten and your individual digestive system.
Individual differences in digestive tendencies somewhat help to determine how nighttime eating might impact oneself. For example, if you are someone who experiences acid-reflux often, eating right before bed might exacerbate this, as studies show that a shorter period of time between eating and going to bed is associated with increased reflux (Fujiwara, 2005).
For the most part, the scientific research out there agrees that consuming a large, high-caloric, mixed meal right before bedtime is not the best idea. Although our bodies certainly multitask in many ways, digesting heavy meals while sleeping doesn’t seem to be preferable. One reason for why digestion may not be as smooth of a process when the body is asleep is because the metabolism slows down. One particular study found that when identical meals were consumed either in the morning, afternoon, or night, the thermic response seems to be lowest at nighttime. The result of this is poor digestion which can come with a variety of symptoms ranging from nausea to stomach discomfort.
That said, other research has suggested that people are able to comfortably digest smaller snack-like, nutrient-dense, low energy foods before bed. In fact, certain foods are believed to have positive effects when eaten around bedtime such as promoting sleepiness, protein synthesis and cardiometabolic health (Kinsey, 2015). One research study points towards walnuts as a potentially healthful bedtime snack, highlighting their concentration of melatonin, a critical hormone for sleep cycle regulation (Reiter, 2005).
In summary, food has a major impact on our wellbeing. As we learn more about the effects of food, we can break through the myths and make better decisions for our health.
Niland, Benjamin, and Brooks D Cash. “Health Benefits and Adverse Effects of a Gluten-Free Diet in Non-Celiac Disease Patients.”Gastroenterology & hepatology vol. 14,2 (2018): 82-91.
Leonard, Maureen M et al. “Celiac Disease and Nonceliac Gluten Sensitivity: A Review.”JAMAvol. 318,7 (2017): 647-656. doi:10.1001/jama.2017.9730
Hyman, Mark.Food: What the Heck Should I Eat? Little, Brown and Company, 2018.
Publishing, Harvard Health. “Are Eggs Risky for Heart Health?”Harvard Health, 2019
Publishing, Harvard Health. “The Sweet Danger of Sugar.”Harvard Health, 2019
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Feskanich, Diane et al. “Milk consumption during teenage years and risk of hip fractures in older adults.”JAMA pediatrics vol. 168,1 (2014): 54-60. doi:10.1001/jamapediatrics.2013.3821
Sonneville, Kendrin R et al. “Vitamin d, calcium, and dairy intakes and stress fractures among female adolescents.”Archives of pediatrics & adolescent medicine vol. 166,7 (2012): 595-600. doi:10.1001/archpediatrics.2012.5
Loma Linda University Adventist Health Sciences Center. "New study associates intake of dairy milk with greater risk of breast cancer: Evidence suggests consistently drinking as little as one cup per day may increase rate of breast cancer up to 50%." ScienceDaily. ScienceDaily, 25 February 2020.
Bayless TM, Brown E, Paige DM. Lactase Non-persistence and Lactose Intolerance.Curr Gastroenterol Rep. 2017;19(5):23. doi:10.1007/s11894-017-0558-9
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Kinsey, Amber W, and Michael J Ormsbee. “The health impact of nighttime eating: old and new perspectives.”Nutrients vol. 7,4 2648-62. 9 Apr. 2015, doi:10.3390/nu7042648
Reiter RJ, Manchester LC, Tan DX. Melatonin in walnuts: influence on levels of melatonin and total antioxidant capacity of blood.Nutrition. 2005;21(9):920-924. doi:10.1016/j.nut.2005.02.005