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What is anxiety?
“Anxiety” is defined in the Merriam-Webster dictionary as “apprehensive uneasiness or nervousness usually over an impending or anticipated ill.”
What are some symptoms of anxiety?
Anxiety is very common and affects many people at some point in their lives.
However, if symptoms last for more than 6 months and cause significant stress or impairment, it could be a sign of a formal anxiety disorder.
These notes will focus on the most common type of anxiety disorder – generalized anxiety disorder.
Common symptoms of generalized anxiety disorder include (1):
- Chronic, excessive, worrying about many topics
- Worrying that is difficult to control
- At least 3 of the following physical symptoms in adults (or 1 in children):
- Feeling restless, keyed up, or on edge
- Easily fatigued
- Difficulty concentrating
- Irritability
- Muscle tension (often linked to headaches or other bodily pains)
- Sleep disturbances
Many people initially go to their primary care provider complaining of headaches or GI disturbances and are later diagnosed with anxiety (69). In children, stomach upset is a common initial complaint (2).
What is the prevalence of generalized anxiety disorder?
Generalized anxiety disorder is estimated to affect 5.7% of Americans at some point in their lives (roughly 1 in 20 people) (3).
It affects roughly twice as many women as men (3).
What are some factors associated with increased risk for anxiety?
The following factors are associated with a greater risk of developing anxiety:
1. Chronic stress
High levels of cortisol (but low cortisol awakening response) have been linked to generalized anxiety disorder in both children and adults (4, 5, 6, 7).
Animal studies suggest that chronic stress may disrupt the functioning of the amygdala (the emotion-processing center of the brain) and impair endocannabinoid signaling (which may partially explain why CBD is a promising therapy for anxiety) (8).
2. Stress and trauma early in life
Emotional, physical, and/or sexual abuse during childhood increases the risk of developing anxiety in adulthood (9).
3. Excessive inflammation
This relationship may be bi-directional. High levels of inflammation may induce feelings of anxiety in some people, while psychological stress may also trigger inflammation (10, 11, 12).
4. High levels of oxidative stress
Chronic high levels of oxidative stress have been correlated with many diseases, including anxiety disorders (13, 14, 15).
5. High intake of processed foods
There is an association between a high intake of processed foods and symptoms of anxiety, but more research is needed to understand why (16).
6. Genetics/Family History
According to twin studies, the heritability of anxiety disorders is ~ 30 to 50%, and anxiety disorders are 4 to 6 times more common in people with diagnosed 1st-degree relatives (17, 18).
The genetics of anxiety disorders are still being studied, but some preliminary data suggests the following genes might play a role:
1. MAOA
The MAOA gene codes for the monoamine oxidase A enzyme, which breaks down serotonin and histamine.
The MAOA G941T polymorphism was associated with generalized anxiety disorder in one small analysis (19).
Additionally, the “long” polymorphism of a region upstream of this gene has been linked to generalized anxiety disorder as well (20).
2. 5-HTTLPR
The short/short SLC6A4 polymorphic region of the 5-HTTLPR gene has been linked to generalized anxiety disorder (21).
This gene codes for a serotonin transporter, and the short polymorphisms are less active.
3. 5-HT1A
The C1019G polymorphism (rs6295) of the 5-HT1A gene has also been linked to generalized anxiety disorder (22).
This gene codes for the serotonin 1-A receptor.
(These links suggest a role for serotonin in generalized anxiety disorder…)
4. CAMKMT
One meta-analysis found a link between the intronic rs1067327 polymorphism of the CAMKMT gene and anxiety.
This gene codes for calmodulin-lysine N-methyltransferase, which is involved in breaking down the amino acid lysine (23).
5. BDNF
A higher frequency of the BDNF 66Met allele has been linked to generalized anxiety disorder, but another study did not find any link (24, 25).
The BDNF gene codes for a protein called brain-derived neurotrophic factor, which impacts neuroplasticity.
7. Environmental Pollution
There is some evidence of a link between environmental toxin exposure and increase diagnosis of anxiety disorders, but it is not clear if this is a causal relationship.
Some of the chemicals that have been studied and linked to anxiety include:
- Fine particulate matter (like from freeway pollution) (26)
- Oil spills (27)
- Organic solvents (commonly used in dry cleaning, paint thinner, nail polish remover, and other industrial cleaners) (28)
8. Gut dysbiosis / leaky gut
It has long been known that the gut and brain have direct bi-directional communication with each other via the autonomic and enteric nervous system, neuroendocrine system, and the immune system, but recently, research has been digging deeper into the link between gut health and anxiety.
One study found that people with generalized anxiety disorder have reduced microbial diversity in their guts with overgrowths of unhealthy bacteria like Escherichia-Shigella, Fusobacterium, and Ruminococcus gnavus (29).
It has also been shown that administration of LPS (lipopolysaccharide, an endotoxin) in humans is linked to increased inflammation, cortisol, and norepinephrine and greater feelings of anxiety (30).
What are some diet and lifestyle changes that can help reduce anxiety?
The following diet and lifestyle recommendations may help alleviate symptoms of anxiety:
1. Exercise
A meta-analysis of studies including more than 42,000 participants found that regular exercise reduced anxiety symptoms by 34% and was most beneficial for people with diagnosed disorders vs just mild anxiety (31).
2. Good Sleep Hygiene
- Maintain a regular sleep schedule, even on weekends
- Avoid alcohol, caffeine, or nicotine in the evening
- Avoid using screens at night (computer, phone, tv, etc)
3. Meditation
MBSR (Mindfulness-Based Stress Reduction) is an effective tool for reducing symptoms of anxiety disorders long-term (32, 33, 34).
It is a structured 8-week program that can be done online or in-person in a group setting, led by a certified instructor.
It can also be helpful in reducing day-to-day anxiety levels in generally healthy adults (35).
New data suggests that it may work by reducing the stress response and systemic inflammation (36).
4. Cutting Out Caffeine
Some (but not all) people with anxiety are sensitive to caffeine and abstaining may improve symptoms. It’s worth a try! (37)
It appears that people with the1976C>T and 2592C>Tins genetic polymorphisms of the A2a receptor are at a greater risk of caffeine-induced anxiety (38).
5. Omega-3 Supplementation
2.5 grams of omega-3s per day (~2g EPA & 0.35g DHA) have been shown to reduce inflammation by 14% and anxiety by 20% in stressed-out medical students without formal anxiety disorders (possibly due to their anti-inflammatory effects) (39).
6. Antioxidants
Since oxidative stress is linked to increased risk of anxiety disorders, diets rich in antioxidants may be protective.
One study found that people with anxiety and depression tended to have low levels of vitamin A, C, and E, and that supplementing for 6 weeks to correct the deficiencies was able to reduce anxiety symptoms (40).
Additionally, diets rich in antioxidants are associated with lower rates of anxiety (and vice-versa) (41).
7. Kava
Kava is a traditional beverage made from the plant Piper methysticum.
It is believed to have natural anti-anxiety effects due to the kavalactones it contains.
Generally speaking, doses of 45 to 85mg kavalactones, 3x per day (135 to 250 mg total) for at least 3 weeks are recommended for anti-anxiety effects (42, 43, 44, 45, 46). It appears to be safe to take daily for 6 months as well (47).
One study found even found that 400mg/day of kava extract is as effective as the anti-anxiety drugs buspirone and opipramol as reducing symptoms of generalized anxiety disorder after 8 weeks (48).
NOW Foods makes a 250 mg supplement containing 30% kavalactones (note that it also contains a type of ginseng to counteract the sleepiness that pure kava can cause, so it might be better for daytime use).
It can also be consumed as a powder, but it is harder to standardize the dose that way.
8. L-lysine and L-arginine
L-lysine and L-arginine are amino acids that can affect the neurotransmitters involved in anxiety.
L-lysine acts as an antagonist to serotonin receptors in the brain and gut, which has been shown to reduce symptoms of anxiety in animals (49).
In human studies, a combination of L-lysine and L-arginine (~3 g each per day) has been shown to reduce feelings of stress-related anxiety in people without diagnosed anxiety disorders (50, 51).
9. Magnesium
Magnesium can affect almost all aspects of the nervous system, and deficiency is believed to play a role in anxiety symptoms (52).
Animal studies show that magnesium deficiency can induce anxious behavior and magnesium levels are negatively correlated with anxiety symptoms (53, 54, 55, 56). However, well-designed human studies are needed.
10. Probiotics
One RCT found that taking a probiotic containing Lactobacillus helveticus R0052 and B. longum R0175 for 30 days significantly reduced feelings of anxiety compared to placebo (but this was in healthy people without anxiety disorders) (57).
11. CBD
Preliminary evidence shows that acute doses of CBD are very effective at reducing anxiety, but more long-term research is needed (58).
This may be because the endocannabinoid signaling symptom is disrupted in people with anxiety disorders (59).
Oral doses of 300 to 600mg have been shown to effectively reduce anxiety compared to placebo (60, 61, 62)
12. Chamomile Extract
Chamomile extract has been shown to help raise the cortisol awakening response, which may reduce anxiety symptoms in people with anxiety disorders (63).
Doses of 1,100 to 1,500 mg (split up into 3 to 5 smaller doses per day) for 8 weeks have been shown to be effective for generalized anxiety disorder (64, 65, 66).
Herb Pharm sells a liquid extract containing 642 mg per serving, while Swanson Superior Herbs sells a capsule containing 500 mg per serving.
13. Passionflower Extract
A preliminary study suggests that 45 drops per day of passionflower extract can be as effective as the anti-anxiety drug oxazepam for reducing anxiety, with fewer side effects (67).
It may also be helpful for reducing anxiety before medical surgery, without causing sedation (68).
Herb Pharm sells a liquid extract containing 619 mg of passionflower extract per serving.
Erica is a registered dietitian nutritionist and lover of science and learning. She has a never-ending passion for education, and gladly spends her time writing & growing this blog! When she’s not at the computer, she can be found in the kitchen with her family, rocking out to good music and cooking up a storm.