Sweetened Drinks Associated with Increased Depression Risk

Aspartame in Diet Soda

Story at-a-glance -

  • Preliminary study findings report that drinking sweetened beverages – whether they’re sweetened with sugar or artificial sweeteners – is associated with an increased risk of depression.
  • Those who drank more than four cans or glasses of diet soda or other artificially sweetened beverages had a nearly 30 percent higher risk of depression compared to those who did not consume diet drinks. Regular soda drinkers had a 22 percent increased risk.
  • Potential mechanisms through which sugar intake could exert a toxic effect on mental health include causing insulin and leptin resistance; suppressing activity of a key hormone called BDNF, which are critically low in depressed patients; and promoting chronic inflammation, which is thought to be a primary cause of depression.
  • Previous studies have also shown that aspartame has a detrimental effect on brain function, neurological, cognitive, and behavioral health.

By Dr. Mercola

Foods have an immense impact on your body and your brain, and eating whole foods as described in my nutrition plan is the best way to support your mental and physical health.

Avoiding sugar (particularly fructose) and artificial sweeteners is in my view, based on the evidence, a very important aspect of preventing and/or treating depression. Both contribute to chronic inflammation, and can wreak havoc with your brain function.

Preliminary study findings that will be presented at the 65th annual meeting of the American Academy of Neurology reports that drinking sweetened beverages – whether they’re sweetened with sugar or artificial sweeteners – is associated with an increased risk of depression. Coffee was associated with a slightly reduced risk.

As reported by WebMD:1

“Researchers say the findings suggest that cutting down on sweetened drinks or replacing them entirely with non-sweetened beverages may help lower depression risk.”

The study included nearly 264,000 American adults over the age of 50, who were enrolled in an AARP diet and health study. At the outset of the study, the participants filled out a detailed dietary survey. At a 10-year follow-up, they were asked whether they’d been diagnosed with depression at any point during the past decade.

  • Those who drank more than four cans or glasses of diet soda or other artificially sweetened beverages had a nearly 30 percent higher risk of depression compared to those who did not consume diet drinks
  • Regular soda drinkers had a 22 percent increased risk

Meanwhile, those who drank four cups of coffee per day had a 10 percent decreased risk of depression, compared to those who drank none. Researcher Honglei Chen, MD, PhD, of the National Institutes of Health (NIH) told WebMD:

“While our findings are preliminary, and the underlying biological mechanisms are not known, they are intriguing and consistent with a small but growing body of evidence suggesting that artificially sweetened beverages may be associated with poor health outcomes.”

While the featured research does not prove causation, and some have pointed out that those who are depressed may turn to sweets for self-soothing, there is plenty of other evidence indicating that both sugar and artificial sweeteners can have a significant and detrimental impact on mental health, so the findings really are not at all surprising. As for the underlying mechanisms, previous research has offered up a number of compelling clues.

Why Sugar Can Increase Depression Risk

Let’s start with sugar. There are at least three potential mechanisms through which refined sugar intake could exert a toxic effect on mental health:

  • Sugar (particularly fructose) and grains contribute to insulin and leptin resistance and impaired signaling, which play a significant role in your mental health
  • Sugar suppresses activity of a key growth hormone called BDNF (brain derived neurotrophic factor) which promotes healthy brain neurons. BDNF levels are critically low in both depression and schizophrenia, which animal models suggest might actually be causative
  • Sugar consumption also triggers a cascade of chemical reactions in your body that promote chronic inflammation. In the long term, inflammation disrupts the normal functioning of your immune system, which is linked to a greater risk of depression

In 2004, noted British psychiatric researcher Malcolm Peet published a provocative cross-cultural analysis of the relationship between diet and mental illness.2 His primary finding was a strong link between high sugar consumption and the risk of both depression and schizophrenia. According to Peet:

“A higher national dietary intake of refined sugar and dairy products predicted a worse 2-year outcome of schizophrenia. A high national prevalence of depression was predicted by a low dietary intake of fish and seafood. The dietary predictors of... prevalence of depression are similar to those that predict illnesses such as coronary heart disease and diabetes, which are more common in people with mental health problems and in which nutritional approaches are widely recommended. Dietary intervention studies are indicated in schizophrenia and depression.”

One of the key predictors of heart disease and diabetes is in fact chronic inflammation, which, as Peet mentions, is also associated with poor mental health. And sugar consumption is a primary driver of chronic inflammation in your body, so consuming excessive amounts of sugar can truly set off an avalanche of negative health events – both mental and physical.

Following my recently revised nutrition plan is a simple way to automatically reduce your intake of sugar from all sources. Another previous study published in the International Breastfeeding Journal,3 found that inflammation may be more than just another risk factor. It may in fact be THE risk factor that underlies all others... According to the researchers:

“The old paradigm described inflammation as simply one of many risk factors for depression. The new paradigm is based on more recent research that has indicated that physical and psychological stressors increase inflammation. These recent studies constitute an important shift in the depression paradigm: inflammation is not simply a risk factor; it is the risk factor that underlies all the others.

Moreover, inflammation explains why psychosocial, behavioral and physical risk factors increase the risk of depression. This is true for depression in general and for postpartum depression in particular.”

Omega-3 Fats are Also Vital for Your Optimal Brain Function and Mental Health

Another major culprit that encourages inflammation in your body is rancid or oxidized omega-fats (think trans fats), whereas a diet rich in omega-3 fats helps to reduce inflammation. Healthy omega-6 fats like gamma linoleic acid (GLA), found in evening primrose, black currant seed and borage oil can also help counteract inflammation.

As you may already know, I recommend taking animal-based omega-3 supplements for many types of inflammation, and for optimal brain health. Most alternative health practitioners are also well aware of the benefits of omega-3’s for depression. While all omega-3 fats possess immune-boosting qualities, omega-3 fats from marine sources (EPA and DHA) are more biologically potent than omega-3 fat ALA found in plant sources such as flax seeds, and are more potent inflammation fighters. My favorite source of omega-3 fats is krill oil, as it has several advantages over fish oil.

Artificial Sweeteners and Depression

The artificial sweetener aspartame is the number one source of side-effect complaints to the FDA, with over 10,000 complaints filed and over 91 symptoms documented that are related to its consumption. Among them are mental adverse effects such as depression and panic attacks. The following video will familiarize you with some of the terrifying side-effects and health problems you could encounter if you consume products containing this chemical. Unfortunately, aspartame toxicity is not well-known by doctors, despite its frequency.

A number of studies have shown that aspartame has a detrimental effect on brain function, neurological, cognitive, and behavioral health. For a listing of such studies, please see my Aspartame Studies page. For example:

  • In a 1986 evaluation of reactions to food additives,4 aspartame (in commonly consumed amounts) was linked to mood alterations (anxiety, agitation, irritability, or depression), headaches, insomnia, dizziness, and fatigue
  • A 1993 study5 found that individuals with mood disorders are particularly sensitive to aspartame, suggesting its use in this population should be discouraged. In the clinical study, the project was halted by the Institutional Review Board after a total of 13 individuals had completed the study because of the severity of reactions within the group of patients with a history of depression
  • A 2006 study6 found that high concentrations of aspartame can cause neurological symptoms, including memory and learning problems
  • In 2008, researchers asserted that excessive aspartame ingestion might be involved in the pathogenesis of certain mental disorders (DSM-IV-TR 2000) and also in compromised learning and emotional functioning7

Humans Cannot Compensate for Methanol Toxicity

Aspartame is primarily made up of aspartic acid and phenylalanine. The phenylalanine has been synthetically modified to carry a methyl group, which provides the majority of the sweetness. That phenylalanine methyl bond, called a methyl ester, is very weak, which allows the methyl group on the phenylalanine to easily break off and form methanol. (This is in sharp contrast to naturally-occurring methanol found in certain fruits and vegetables, where it is firmly bonded to pectin, allowing the methanol to be safely passed through your digestive tract.)

Methanol acts as a Trojan horse; it's carried into susceptible tissues in your body, like your brain and bone marrow, where an enzyme called alcohol dehydrogenase (ADH) converts it into formaldehyde, which wreaks havoc with sensitive proteins and DNA. Interestingly, and most importantly, humans are the only animals that do NOT have a protective mechanism to compensate for methanol toxicity...

Both animals and humans have small structures called peroxisomes in each cell. There are a couple of hundred in every cell of your body, which are designed to detoxify a variety of chemicals. Peroxisome contains catalase, which help detoxify methanol. Other chemicals in the peroxisome convert the formaldehyde to formic acid, which is harmless, but this last step occurs only in animals. When methanol enters the peroxisome of every animal except humans, it gets into that mechanism. Humans do have the same number of peroxisomes in comparable cells as animals, but human peroxisomes cannot convert the toxic formaldehyde into harmless formic acid.

So, in humans, methanol is allowed to be transported in your body to susceptible tissues where this enzyme, ADH, then converts it to formaldehyde, which damages your protein and DNA, which of course can lead to all sorts of health issues.

Don’t Be Fooled by the Aspartame Propaganda

Aspartame proponents claim it’s harmless, pointing out that phenylalanine and aspartic acid can be readily found in whole foods. However, comparing aspartame to whole food is really comparing apples to oranges.

In a normal protein like meat, fish or eggs, phenylalanine and aspartic acid comprise 4-5 percent each of the total amino acid profile. This is how nature intends the human body to encounter these two amino acids and there is nothing wrong with these substances if they occur naturally in a proper balance with other amino acids. But in aspartame the ratio of these two amino acids is 50 percent phenylalanine and 40 percent aspartic acid (with 10 percent methyl ester bond, aka wood alcohol, a known poison).

In other words, on a percentage basis this is a massive quantity of two unnaturally isolated amino acids that are simply not found in this ratio in nature, bonded together by a known poison. The result of this chemical cocktail is a sweet tasting neurotoxin.

As a result of its unnatural structure, your body processes the amino acids found in aspartame very differently from a steak or a piece of fish. The amino acids in aspartame literally attack your cells, even crossing the blood-brain barrier to attack your brain cells, creating a toxic cellular overstimulation, called excitotoxicity. MSG is another excitotoxin, and works synergistically with aspartame to create even more damage to your brain cells.

The truth is, aspartame should never have been approved, and it should not be on the market, considering how many complaints the FDA has received by people who experienced frightening and devastating side effects from it. (To get the back-story of how it got approved in the first place, please see my previous article Proven Unsafe But FDA-Approved: Are YOU Still Consuming This Man-Made Poison?)

The only way to put pressure on the FDA to address the very real hazards of aspartame (and other artificial sweeteners) is to keep adding to the mounting pile of complaints. So please, if you experience an adverse reaction to any aspartame product, I urge you to call the FDA Consumer Complaint Coordinator in your area, and file an adverse event report.

Key Factors to Overcoming Depression

There’s no doubt in my mind that radically reducing or eliminating all forms of sugar and artificial sweeteners from your diet is a crucial step to prevent and/or address depression. Quite simply, if you fail to address the root of the problem, you could be left floundering and struggling with ineffective and potentially toxic band-aids for a long time. Your diet does play a huge part in your mental health so please do not ignore the impact sugar and artificial sweeteners might be having. Here are six additional strategies that can help you even further:

  1. Exercise – If you have depression, or even if you just feel down from time to time, exercise is a MUST. The research is overwhelmingly positive in this area, with studies confirming that physical exercise is at least as good as antidepressants for helping people who are depressed. One of the primary ways it does this is by increasing the level of endorphins, the "feel good" hormones, in your brain. It also helps to normalize your insulin and leptin signaling.
  2. Eat a healthy diet – A factor that cannot be overlooked is your diet. Foods have an immense impact on your mood and ability to cope and be happy, and eating whole foods as described in my nutrition plan will best support your mental health. Avoiding sugar and grains will help normalize your insulin and leptin levels, and eliminating artificial sweeteners will eliminate your chances of suffering its toxic effects.
  3. Optimize your gut healthFermented foods, such as fermented vegetables are also important for optimal mental health, as they are key for optimizing your gut health. Many fail to realize that your gut is literally your second brain, and can significantly influence your mind, mood, and behavior. Your gut actually produces more mood-boosting serotonin than your brain does.
  4. Support optimal brain functioning with essential fats – I also strongly recommend supplementing your diet with a high-quality, animal-based omega-3 fat, like krill oil. This may be the single most important nutrient to battle depression.
  5. Get plenty of sunshine – Making sure you're getting enough sunlight exposure to have healthy vitamin D levels is also a crucial factor in treating depression or keeping it at bay. One previous study found that people with the lowest levels of vitamin D were 11 times more prone to be depressed than those who had normal levels. Vitamin D deficiency is actually more the norm than the exception, and has previously been implicated in both psychiatric and neurological disorders.
  6. Address your stress – Depression is a very serious condition, however it is not a "disease." Rather, it's a sign that your body and your life are out of balance. This is so important to remember, because as soon as you start to view depression as an "illness," you think you need to take a drug to fix it. In reality, all you need to do is return balance to your life, and one of the key ways to doing this is addressing stress.
  7. Meditation or yoga can sometimes help. If weather permits, get outside for a walk. But in addition to that, I also recommend using a system that can help you address emotional issues that you may not even be consciously aware of. For this, my favorite is Emotional Freedom Technique (EFT). However, if you have depression or serious stress, I believe it would be best to consult with a mental health professional who is also an EFT practitioner to guide you.