In 2009, a mere one percent of the population was vegan or vegetarian. Currently, five percent of the population has made the switch to a vegan or vegetarian lifestyle.  Half of this crowd is strictly vegan. This is a 500% increase in veganism in less than a decade.
Related: Vegan Diet Plan for Building Muscle
This equates to about 8 million vegans in the US alone. In total, about 16 million Americans consume no animal products.
But the growth of veganism and vegetarianism is not limited to the US. In the UK there has been a 350% increase of those opting for a vegan diet since 2006.  Of these converts, about 42% of vegans were between the ages of 15 and 34. 14% of the over 65 crowd had made the switch.
A few more statistics for you to chew on: 
- 42% of vegan converts claim they made the jump after watching a vegan-focused documentary or film.
- 69% of vegans list as a primary reason for their dietary choice as a method to support the ethical treatment of animals.
- 45% made a slow but gradual transition over to veganism.
- 52% of vegans have adhered to this lifestyle for less than 10 years. This is obviously due to the growth of this eating lifestyle.
Google is also showing a boom in vegan interest. In 2007 there were only 1,600 searches a month. In 2014, "vegan" searches reached 24,000 per month. Currently, there are 110,000 vegan-related searches per month. 
6 Supplements for VegansWhile there are many health benefits associated with a vegan diet, there are also certain limitations. Some nutrients can only be derived from plants, while others come solely from animals. When opting to make the switch to a vegan lifestyle, it is best to be aware of these nutritional challenges and possible deficiencies.
What follows is an analysis of some of the challenges associated with a vegan diet. Understand that while most supplements are manufactured using plant sources (because of the cost) rather than meat sources, you should still research each company to make sure that the products you are supplementing with are vegan-friendly.
#1 - Vitamin B12
While vitamin C can only be found in plant food sources, vitamin B12 is almost exclusively found in animal products. A vitamin B12 deficiency is very common for vegans. In fact, one specific study revealed that 92% of vegans showed some form of a vitamin B12 deficiency. 
The normal range for serum vitamin B12 levels in the human body is 200 to 900 pg/ml. The vast majority of vegans came in below 200 pg/ml. 64% of lactovegetarians were also vitamin B12 deficient, while 47% of lacto-ovovegetarians and 20% of semi-vegetarians also experienced deficient levels.
The RDA's recommend daily intake of vitamin B12 is 6mcg. This can be found in products such as Machine Multi.
it should be noted that the human body processes vitamin B12 efficiently. It only absorbs what it needs. Therefore, it's hard to take in too much vitamin B12. Excess amounts are flushed out of your system.
#2 - Creatine
Creatine is another animal exclusive. It is found only in organ and muscle tissue. While the human body is capable of producing about half of the creatine it requires for normal functioning, the other half must come from our food choices.
In a relative sense, both vegans and vegetarians are in a state of creatine deficiency. Supplementation with 2 to 5 grams daily is recommended. This will help to being muscle creatine stores back up in the normal range.
Without creatine, the body will lack in four major areas:
- A decrease in anaerobic endurance.
- Reduction in strength/power output.
- Dampered glucose tolerance.
- Restriction of cognitive functioning during sleep deprivation.
#3 - High Quality Protein
Not all protein sources are created equal. Animal protein foods are generally much higher quality, and contain essential amino acids in the right ratios.  Yes, plant-based foods provide protein, but it takes some time and effort to put together a well-rounded vegan diet that covers all your amino acid bases.
Dr. Ray Peat, PhD, explains:
"One thing that happens in the vegetable diet, heavily based on [the] cabbage family, or beans, lentils and nuts, these proteins, in quality, rank about 15 times lower than the highest quality protein. And so even though a person might think they're eating nothing but protein rich foods, beans, and nuts, their quality is so low that their liver simply can't respond to the thyroid."Of the 20 amino acids, there are nine that the body can't manufacture internally. These are called essential amino acids. A "complete protein" must contain all nine of these aminos in roughly equal amounts. While eggs and meat are complete protein foods, vegan choices such as nuts and beans are not.
All vegans, especially those that are athletic and enjoying working out, need to consider supplementing with a well-rounded, vegan-friendly protein source.
#4 - Beta-Alanine or Carnosine
Carnosine is found only in animal products. It is dipeptide molecule comprised of two amino acids: histidine and beta-alanine. Carnosine is located in brain and muscle tissue in a very high concentration. Carnosine is a metabolic product of beta-alanine.
A non-essential amino acid, beta-alanine works to increase carnosine levels in skeletal muscle tissue. One study revealed that a beta-alanine supplement has been shown to increase carnosine levels by 20 to 80% in as little as two weeks. 
So why is carnosine so important? Carnosine assists with anti-aging, working to protect against a number of degenerative processes and disease. Some of the degenerative conditions carnosine works against are Alzheimer's, diabetes, atherosclerosis, and chronic renal failure.
A daily dosage of 2 grams of beta-alanine is optimal. This is a low-end intake. An average of 2.4g to 6.2g per day may be more optimal.
Beta-alanine can be taken as a stand-alone supplement, or as a compliment to many popular pre-workout formulas that contain smaller quantities of beta-alaine such as MTS Clash.
#5 - Carnitine (NOT Carnosine)
Carnitine is a dipeptide compound comprised of the essential amino acids methionine and lysine. Carnitine plays an important role in the metabolism of energy, and works to improve energy flow to the brain. it also plays a role in the lowering of stress levels.
It is also useless in the battle against diabetes, and for improving skin health. 
Carnitine is almost exclusively found in meat. Therefore, vegans are likely to find themselves in a carnitine-deficient state.
Carnitine is produced in the body through the liver and kidneys when lysine and methionine are processed. If you are consuming enough of these essential amino acids, then odds are you do not need to supplement with carnitine. If you are unsure of your essential amino acid intake, or it varies from day to day due to an inability to maintain a consistent eating protocol, then carnitine supplementation is a wise decision.
A minimum daily dosage of 500 mgs should be sufficient for the average vegan.
#6 - Iodine
Iodine might be the surprise of this group.
Vegans and vegetarians who avoid things such as processed foods and table salt might be at risk for an iodine deficiency. Obviously, a healthy diet generally avoids these items in excessive amounts, so it is wise for a vegan to consider additional iodine intake.
Seaweed is very iodine-rich. Fish is also rich in iodine, but obviously not a part of the vegan diet.
In general, 30% of the world's population do not take in enough of this vital nutrient.  Iodine deficiency can lead to lower IQs in children, so it is a very important nutrient for pregnant vegans and children who consume a vegan diet.
Adults need to consume about 150 mcg daily. Too much or too little iodine can lead to thyroid issues, leading to wonky energy regulation in the human body. It is generally recommended that adult restrict iodine consumption to no more than 600 mcg daily. 
Please consult your physician before supplementing if you are unsure about your current intake. Products such as Machine Greens Plus Multi contain a safe amount of supplemental iodine - 20 mcg per serving. Furthermore, each individual capsule of Machine Greens contains approximately 3.3 mcg of iodine