23 Reasons To Eat More Zinc-Rich Foods

Could you be missing this vital nutrient because of your diet? Find out if you’re not getting enough and missing out on the benefits of zinc.

In today’s 24/7 society of constant connectivity and longer work days, many people are struggling to keep up.

How can you stay on top of your work deadlines, find time to exercise, and have enough energy for family and friend time in the evening?

Fatigue, low mood, frequent colds and flu, and lack of vitality are more and more commonplace. While there are a number of essential vitamins and minerals, there are a select few that influence many key areas of your health. Zinc is one of those “all-star” nutrients.

Almost 20 percent of the population is at risk of overt zinc deficiency, while insufficient intake — a level at which your intake doesn’t meet your daily needs — is seen in almost one out two people. (1)

How important is zinc? It’s involved in over 300 different chemical reactions in the body. From immunity to wound healing, healthy skin to libido, zinc packs a serious health punch.

Here are 23 ways zinc can supercharge your health.

#1 Stops Cold and Flu

If you struggle with catching too many colds or flus, or find you’re always getting sick, then upgrading your zinc intake should be a top priority.

Zinc helps to supercharge the production of your first line of immune defense immune soldiers, neutrophils and natural killer cells, which means more protection for you from nasty bugs. (2)

#2 Supports Robust Metabolism

Whether it’s long days at the office or intense exercise sessions at the gym, stress is one of the primary causes of sluggish thyroid function and weight gain. Prolonged stress can decrease levels of both T4 and T3 thyroid hormone. Ensuring adequate zinc intake can protect against this effect. (3)

#3 Boosts Testosterone

Testosterone is equally important for both men and women. It’s vital for building lean muscle, keeping bones strong, supporting a healthy heart, and boosting libido. Zinc supports the production of testosterone at a cellular levels in the testes in men and ovaries in women if your levels are low. (4)

#4 Improves Blood Sugar

Maintaining steady blood sugar levels throughout the day is a hallmark of good health and maintaining an ideal body composition. Research in children shows increasing zinc intake has a dramatic improvement on fasting blood sugar levels. (5)

#5 Improves Insulin Function

If you’re overweight, out of shape, or in poor health, then you likely have poor insulin sensitivity. Insulin, your blood sugar hormone, has a powerful influence on weight gain and risk of chronic disease. Numerous studies show that zinc plays a key role in improving insulin sensitivity, helping to combat weight gain and chronic disease. (6)

#6 Optimizes Stomach Acid

Your stomach is in charge of breaking down the food you eat so you can absorb all the wonderful nutrients in your meal. This requires robust levels of stomach acid (HCl) to be produced.

Unfortunately, people are so busy at work that they often eat lunch without even leaving their desk, which can hinder HCl output, as can diets low in zinc, which is required to support the parietal cells that produce HCl. Vegetarians typically have lower stomach acid levels than meat eaters, and their diets are also lower in zinc. (7)

#7 Improves Fertility

If you’re trying to conceive, and you want to keep your “swimmers” strong (or your partner’s) then ensuring adequate zinc status is very important. Add some of the zinc-rich foods at the end of this post to increase your intake to improve fertility. (8)

#8 Fixes Acne Problems

Struggling with chronic acne? Nutrient deficiencies and poor nutrient absorption are often overlooked by today’s doctors. The research shows a strong correlation between low levels of zinc and increased severity of acne. (9)

#9 Boosts Low Mood

There are many factors that impact low mood and depression. On the nutrition front, correcting low zinc levels has been shown to reduce anger and incidence of depression in young women. (10)

#10 Supports Healthy Growth In Toddlers

Infants and young children are at particular risk of zinc deficiency. (11) If your child is not growing at the same rate as his or her peers, zinc deficiency may be a root cause.

The likelihood of low “height-for-age” in children under 5 years old has been recommended as an indirect indicator of zinc deficiency and when the prevalence of slow growth is greater than 20 percent, the risk of zinc deficiency is elevated. (12)

#11 Acts As Aromatase Inhibitor

If you’ve been struggling with weight gain and have increased belly fat, an enzyme called aromatase ramps up in fat cells that converts your muscle-building testosterone into fat-building estrogen.

The more overweight you are (particularly around the midsection, more commonly seen in men), the worse things get. Zinc acts as an aromatase inhibitor, which blocks this conversion… which is a good thing!

#12 Reduces DHT Levels

Another factor that reduces testosterone levels, particularly in men with male-pattern baldness or significant body hair, is the conversion of testosterone to DHT (dihydrotestosterone).

Like the aromatase enzyme, zinc helps to block the conversion of testosterone to DHT. (13) This is very good news because DHT is a much weaker form of testosterone and doesn’t provide the mood-boosting, muscle-building, or healthy heart-supporting benefits that regular testosterone does.

#13 Speeds Wound Healing

Fall off your bike lately? Snowboarding accident? Or simply cut yourself shaving? Zinc is an essential mineral that supports collagen formation, helping to rebuild tissue and accelerate wound healing. (14)

#14 Stops The Ringing In Your Ears

Tinnitus is the medical term for ringing in your ears. In traditional Chinese medicine, being fatigued or rundown is tops on the list and in clinical practice high coffee intake (inhibits absorption of key minerals, like zinc, when taken with food) is also a primary culprit. The research shows that low zinc levels also may play a key role. Bump up your zinc levels and see if it’s the quick fix you need. (15)

#15 Increases Muscular Strength

Do you struggle with low back pain? How about low vitality and energy? Building strength in the gym is a great way to fight off all of these ailments. (Recall the famous quote… “only the strong survive!”)

If you do start going to the gym, adding more zinc into your nutritional arsenal has been shown to support significant increases in strength. (16)

#16 Supercharges Your Libido

Oysters have been traditionally viewed as an aphrodisiac, boosting libido and sexual vigor. It’s no coincidence that oysters are head and shoulders above all other foods when it comes to zinc status. Low libido? Eat more super zinc-rich oysters!

#17 Reduces Inflammation

If you’re overweight or in poor health, you’re likely suffering from some degree of systemic inflammation. Experts agree that high levels of inflammation are a root cause of many of today’s chronic diseases.

Getting enough zinc in your diet can help reduce pro-inflammatory cytokine molecules and reduce CRP levels in the body, a classic marker for systemic inflammation. (17)

#18 Boosts Brain Function

Brain-derived neurotrophic factor (BDNF) is a potent mood-boosting chemical that is decreased in athletes training intensely, overweight individuals, or those with systemic inflammation.

Interestingly, a significant positive correlation has been found between zinc and BDNF levels, which supports positive mood and brain function. (18) Another great reason to eat steak! (A great source of zinc).

#19 Fights Off Psoriasis

Approximately 7 million adults suffer from psoriasis, a skin condition marked by red, scaly patches that tend to be quite itchy. Topical zinc creams have been shown to be highly effective at reducing local psoriasis. (19)

#20 Protects Against Anorexia

Anorexia is most common among young women, a group that is also at high risk of zinc deficiency, in particular if they’re vegetarian. The medical journal Eating and Weight Disorders found that insufficient zinc intake adversely affects specific neurotransmitters in the brain and that zinc supplementation is able to correct these abnormalities. (20)

#21 Quenches Free Radical Damage

Your cellular membranes are responsible for communication between all the cells of your body, and free radical damage from a poor diet, lack of exercise, or environmental factors constantly cause free radicals — little fires that must constantly be put out by antioxidants. Zinc acts as an antioxidant to protect cell membranes from free radical damage. (21)

#22 Stops Diarrhea In Kids

If your kids are suffering from bouts of diarrhea, zinc supplementation has been shown to be an effective strategy for reducing both the severity and duration of the illness. (22)

#23 Helps Repair Leaky Gut

Zinc has been found to play a key role in protecting against intestinal permeability or leaky gut, a condition where undigested food, proteins, and bacteria from the gut can enter the bloodstream unimpeded, leading to immune system over-activation and possible autoimmune conditions. (23)

How do you know if you may be low in zinc? Common symptoms include poor immunity, low stomach acid, low testosterone levels, white spots on your finger nails, allergies, thinning hair, or acne.

Blood tests for serum or RBC zinc can help identify frank zinc deficiency, while zinc insufficiency is typically seen when lab results show low white blood cell (WBC) counts, as well as low levels of alkaline phosphatase (ALP).

If you want to upgrade your zinc intake, oysters are your best bet. A 3-ounce serving provides 74mg, almost 500 percent of the daily recommended intake.

Beef and crab are the next best, at about 7mg per 3-ounce portion, and other meats like lobster, pork, and chicken provide 3mg per serving. Vegetable sources include cashews and almonds, at 1.6 and 0.9g per ounce.

If you want to upgrade your health, energy, and vitality, then ensuring your body is getting the right dose of the essential mineral zinc — responsible for over 300 key reactions in the body — is an absolute must.

(This article originally appeared on Paleohacks.com)

Dr. Marc Bubbs ND, CISSN, CSCS


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4-Benefits of Ashwagandha For Performance

Withania somnifera, commonly known as ashwagandha, is a powerful herb that’s been used for centuries in Ayurveda - traditional Indian medicine - to build strength, stamina and combat fatigue. Ashwagandha is classified as an adaptagen herb, which helps the body maintain normal physiological function during times of physical or mental stress, builds resistance to future stressors, and promoter superior vitality and energy.1 Popularly known as Indian ginseng, ashwagandha has a vast array of pharmacological benefits; relaxing a stressed nervous system, lowering blood pressure, supporting superior immunity, reducing inflammation, promoting deep sleep, keeping your memory sharp and acts as an antioxidant.(2)

The question is, if you’re training hard in the gym and looking to add lean muscle can the ancestral benefits of ashwagandha help you build more muscle? Or is this yet another example of exaggerated folklore?

A recent study investigated the benefits of ashwagandha supplementation on 57 adult men, aged 18-50, to see if this “wonder herb” really has what it takes to make you stronger. After eight weeks of training, the ashwagandha group showed significantly greater increases in strength, in a one-repetition maximum for bench press and leg-extension compared to the placebo group (see Figure 1).(3) They also experienced greater muscle hypertrophy in the upper-body (not lower-body) as well as seeing superior improvements in body-composition.(3) (Bigger, stronger AND leaner… Not a bad combination!) The benefits didn’t stop there. The group supplementing with ashwagandha also displayed lower levels of muscular damage, suggesting faster recovery after training, as well as greater testosterone levels.(3) Faster recovery means an increased ability to ramp up training frequency, a great recipe for getting bigger and stronger. Furthermore, intense training tends to lower testosterone levels, making this adaptagen herb a great choice during peaking training phases.

Figure 1 -

If you’re a regular gym-goer or advanced trainee, the added support from adaptagen herb ashwagandha may help get stronger, accelerate recovery and keep your anabolic hormone testosterone in balance. Try adding 300mg of ashwagandha, twice daily for 4 to 8 weeks. If you’re a new trainee and hypertrophy is your goal, remember that achieving your ideal daily protein intake and total caloric intake is absolutely crucial to your success and should be your first priority, before adding the “bells and whistles” of supportive herbs.

It can be difficult to fit all your training into a busy schedule when striving for hypertrophy and lean muscle gains. Ashwagandha doesn’t just help you build muscle and recovery more quickly, but offers added benefits of building a better brain and overall health to offset the stressors of busy workdays, constant connectivity and lack of sleep. This ancestral herb does indeed pack a powerful punch.

 Dr. Marc Bubbs ND, CISSN, CSCS


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1)    Abascal K, Yarnell E. Increasing vitality with adaptogens: multifaceted herbs for treating physical and mental stress. Altern Complement Ther. 2003;9:54–60.

2)    Mishra LC, Singh BB, Dagenais S. Scientific basis for the therapeutic use of Withania somnifera (ashwagandha): a review. Alternative Medicine Review. 2000;5:334–46

3)    Wankhede S. et al.Examining the effect of Withania somnifera supplementation on muscle strength and recovery: a randomized controlled trial Journal of the International Society of Sports Nutrition (2015) 12:43.


The Athletic Potential of Vitamin D

It’s the middle of winter, and the days are dark and cold. But you’re still training intensely and eating clean to get ready for your upcoming competition. Unfortunately, there is one vitamin no amount of clean eating can fix, especially in athletes. New research suggests maintaining the right levels of vitamin D may improve several elements of performance, including your VO2 max, sprint capacity, and power production.

A Growing Research Field

Exercise dramatically increases an athlete’s demand for vitamin D, as your muscle, heart, and vascular tissue all contain key vitamin D receptors. Today, studies show more than 50 percent of athletes are low in vitamin D.1 While the direct cause isn’t clear, it’s most likely a combination of things like inflammatory processes, muscular damage, increased protein synthesis requirements, increased immune activity, lack of sun exposure, race, and genetics.2

A clear vitamin D deficiency occurs at blood levels less than 20ng/mL (< 50 nmol/L), while insufficiency for athletes is generally defined at blood levels between 20-32 ng/mL (50-80 nmol/L). Insufficiency simply means you’re not getting enough to meet the demands of your activity. Intense training is demanding. New research suggests that 40-50ng/mL (100-125 nmol/L) seems to be the “sweet spot” for supporting optimal athletic performance, and experts agree the body needs daily replenishment to meet that requirement.3,4

Achieving your ideal vitamin D intake may upgrade six key areas of performance:

  1. VO2 max
  2. Muscular power production
  3. Testosterone levels
  4. Inflammation
  5. Susceptibility to colds and flu
  6. Mood

Let’s take a closer look at each.

1. VO2 Max

You likely spend a lot of time planning and periodizing your training to maximize your efforts, but did you know that not having enough vitamin D could compromise your maximal oxygen uptake, or VO2 max, a classic marker for assessing aerobic fitness? New research in professional hockey and soccer players found a strong correlation between low vitamin D status and VO2 max. If you’re a weekend warrior, this relationship may be even stronger.

Experts will tell you just because there is an association doesn’t mean that increasing the amount of vitamin D in your diet will improve performance. However, a new study in vitamin D deficient rowers found that 8 weeks of supplementation (6,000IU per day) resulted in more than a 10 percent improvement of VO2 max. For elite athletes, improving performance by 2-3 percent is the difference between a podium finish and being in the middle of the pack.5,6,7 Remember, more is not always better. Talk to your doctor and get tested before supplementing with high doses of vitamin D.

2. Power Production

Your muscle tissues have many key receptor sites for vitamin D, and they seem to play a key role in supporting power production. For athletes, increasing power production translates to improved performance on the playing field. Recently, the Canadian Women’s National Hockey strength and conditioning team found athletes with higher power production were more likely to make the final selection for the national team. 

Additionally, a study in soccer players found increasing baseline vitamin D status over an 8-week period resulted in an increase in 10-meter sprint times and vertical jump.8 While not all studies found this relationship, it’s important to ensure you meet the minimal baseline requirements to ensure maximum training benefit.

3. Testosterone Levels

Low testosterone is a common symptom in athletes who are over-reaching and overtraining. Unfortunately, too many people look for a quick fix rather than address why their testosterone levels are low in the first place. Vitamin D is a precursor to testosterone production and may increase the binding efficiency of testosterone to its receptors.4 Low levels are linked to increased protein breakdown, reduced strength, and increased body fat.

If you’re an athlete over age sixty, the connection is even more compelling because low vitamin D levels at that age correlate strongly to low testosterone levels.9 A new study over a 12-month time span found that adding approximately 3,000 IU of vitamin D daily resulted in increased total, bioavailable, and free testosterone.10 For those training through the winter, low testosterone combined with intense training will lead to sub-optimal recovery and increased risk of symptoms of overtraining (i.e., increased muscle soreness, low mood, fatigue, low libido, etc.). This is especially true for athletes who compete in indoor sports year round that limit sun exposure.

4. Inflammation

Inflammation is a natural product of intense training. However, too much inflammation can impair muscular function and future performance. One study showed adding an extra 4,000 IU of vitamin D daily can offset the increased inflammatory reaction with a high-volume training load of 10 sets of 10 reps of compound exercises in men and women.11

Interestingly, the group adding extra vitamin D also noted a mere 6 percent drop in power output over the course of the workout, while the group not supplementing had a 32 percent decrease in power. Amazingly, this deficit lasted for up to 48 hours. If you’re preparing for a competition or the CrossFit Games, maintaining power output during competition is critical to your performance.

5. Colds and Flu

There is nothing worse than catching a cold or flu in the days leading up to a competition. All those hard training days and dedication to be at the top of your game, only to be cut short by a nasty bug. If you’re low in vitamin D, the “foot soldier” immune cells that make up your innate immune system will also be low. If this first-line of immune defense is compromised, you’ll be at increased risk of infection.12

Vitamin D promotes hundreds of anti-microbial proteins in the body that fight off bacteria and viruses and helps keep your immune system robust in the build-up to competition. Research in athletic populations highlights that maintaining optimal levels of vitamin D can reduce common infectious illnesses.13 If your levels are low, your immunity and performance will likely be compromised.

6. Mood

Training intensely isn’t just tough on your muscles and joints. It also takes a toll on your mental game. If you're an athlete, you regularly push that fine line between over-reaching (pushing beyond your limits to grow stronger) and overtraining (pushing too far beyond your limits). Therefore, it’s crucial to maintain a positive mood as you fight through the toughest weeks of your training.

Low levels of vitamin D are consistently associated with low mood and depression, and because many athletes train indoors through the winter months (and sometimes even summer, depending on your sport), deficient levels can impair you sense of well-being.14 Cognitive decline also impacts your decision-making abilities, which are crucial in the heat of competition, yet fatigue and pain make them very difficult.

Sources of Vitamin D

Now that you know vitamin D is key for optimal performance, where is the best place to get it? The sun is far and away your best source of vitamin D. Fifteen minutes of exposure on 5 percent of your skin leads to 10,000-20,000 IU of vitamin D production.4 If you live in a city with a true winter – north of the 42nd parallel – you’ll need more than sun exposure alone to meet your demands, as the sun isn’t high enough in the sky for an adequate dose.

Including vitamin D rich foods in your diet should always be your foundation, and the best dietary sources include egg yolks, pork (yes, bacon!), mushrooms, fortified milk, and yogurt (if you struggle to digest dairy effectively, discontinue).

Of course, if you live in a city with a true winter climate, food alone won’t meet your demands. The general recommendation for supplementing with vitamin D during winter is 1,000-2,000 IU per day. However, this is the case for the general population, not athletes. The research on athletes suggests between 4,000-6,000 IU of vitamin D3 daily is a good bet, however this should only be taken during your intense training phases (up to 8-12 weeks), or from November to March. If you decide to take vitamin D doses greater than 2,000 IU, you must get regular blood tests done with your doctor.

Give Yourself a Winning Edge

Whether your goal for 2016 is achieving a new personal best or finishing on top of the podium, make sure your vitamin D levels are adequate. Assess your vitamin D status, add more vitamin D-rich foods, and find the right supplement strategy to meet your needs.

Intense training requires a robust nutrition plan to meet your body’s demands, and failing to adequately replenish vitamin D can negatively impact too many key systems to ignore. Get your daily dose of vitamin D this winter. The research shows it can make all the difference.

(Read the rest of my article @BreakingMuscle)

Dr. Marc Bubbs ND, CISSN, CSCS



1. Farrokhyar F, et al., “Prevalence of vitamin D inadequacy in athletes: A systematic review and meta-analysis,” Sport Medicine 5 (2014): 365–78.

2. Willis KS, Smith DT, Broughton KS, Larson-Meyer DE. “Vitamin D status and biomarkers of inflmmation in runners,” Journal of Sports Medicine, 3 (2012): 35-42.

3. Ogan D, Pritchett K. “Vitamin D and the athlete: Risks, recommendations, and benefits,” Nutrients 5 (2013): 1856–1868.

4. Dahlquist D et al. “Plausible ergogenic effects of vitamin D on athletic performance and recovery,” Journal of the International Society of Sports Nutrition, 12 (2015):33

5. Koundourakis N et al. “Relation of vitamin D level to maximal oxygen uptake in adults,” American Journal of Cardiology, 107 (2011):1246–9.

6. Forney L, et al. “Vitamin D status, body composition, and fitness measures in college-aged students,” Journal of Strength and Conditioning Research, 28 (2014): 814–24.

7. Jastrz?bski Z. “Effect of vitamin D supplementation on the level of physical fitness and blood parameters of rowers during the 8-week high intensity training,” Facicula Educ Fiz ?i Sport, 2 (2014): 57–67.

8. Close G et al. “Assessment of vitamin D concentration in non-supplemented professional athletes and healthy adults during the winter months in the UK: implications for skeletal muscle function,” Journal of Sports Science, 31 (2013): 344–53.

9. Wehr et al. “Association of vitamin D status with serum androgen levels in men,” Clinical Endocrinology (Oxf), 73 (2010): 243–8.

10. Pilz S, et al. “Effect of vitamin D supplementation on testosterone levels in men,” Hormone and Metabolic Research, 43 (2011): 223–5.

11. Barker T et al. "Supplemental vitamin D enhances the recovery in peak isometric force shortly after intense exercise," Nutr Metab (Lond), 10 (2013): 69.

12. Youssef D et al. “Vitamin D’s potential to reduce the risk of hospital-acquired infections,” Dermatoendocrinol, 4(2012):167-75.

13. Larson E. “Vitamin D supplementation in athletes,” Nestle Nutrition Institute Workshop Series, 75 (2013): 109-21.

14. Polak M et al. “Serum 25-hydroxyvitamin D concentrations and depressive symptoms among young adult men and women,” Nutrients, 6 (2014): 4720–30.