When approached correctly, a vegan and vegetarian diet is a fantastic way to give your body a pure stream of essential vitamins, minerals, and antioxidants. However, to get the most out of your effort, nutritional knowledge, practice, and discipline are paramount to getting the nutrients you require – especially amino acids and vitamin B12. A journey into the vegetarian and vegan lifestyle without that knowledge may result in your experiencing one or more of the following 10 concerns.
10 Things You Have to Consider When Following a Vegan or Vegetarian Diet
1. B12 Deficiency
Anyone considering a vegan lifestyle needs to be vigilant at receiving adequate vitamin B12, a nutrient primarily available in animal products. B12 deficiency may prompt fatigue, memory concerns, and depression. Supplementation is often necessary for vegans and even vegetarians (and some meat eaters may also benefit from a B12 supplement).  Don't think that because you don't have any outward signs that this doesn't apply to you. Often, the signs of a B12 deficiency aren't apparent for years. 
2. High Levels of Homocysteine
Homocysteine is an amino acid and high levels raise the risk of cardiovascular disease and stroke.  Why would homocysteine levels increase? Take a step back to consideration number one – vitamin B12 provides the main chemicals needed to convert homocysteine into necessary amino acids. Without it, no conversion can take place. A recent review confirmed higher blood levels of homocysteine are typical in vegetarians and vegans compared to people who eat vegetables and meat. 
3. Uric Acid Levels!
Uric acid is created after the body breaks down purines, substances found in some animal and legume products. Uric acid buildup can lead to gout, cardiovascular disease, type II diabetes, and kidney stones. Vegetarians and pescatarians (vegetarians who eat fish) generally have balanced levels of uric acid. People who consume meat seem to have higher levels. Most surprisingly is that many studies suggest vegans have the highest levels of uric acid compared with other groups. 
4. Sexual Performance
For men on a low-fat, vegan diet, receiving the necessary nutrients for normal hormone function can be a challenge. Men who consume soy, a popular protein source for many vegans and vegetarians, should be aware of the food's tendency to encourage estrogen levels and its subsequent impact on male sexual health. For middle-aged men already experiencing a decline in testosterone, consuming soy further compounds the situation. Even the libido of younger men can be negatively affected from soy. Avoiding soy products may be helpful for stimulating sexual function and desire in men. 
5. Issues with Exercise
Physical activity breaks down muscle tissue and good nutrition (and rest) builds it back up. Protein and amino acids are the primary nutrients required for muscle building, and a vegetarian or vegan diet lacking certain amino acids can lead to serious concerns. Vegan athletes who do not receive an adequate supply of all essential amino acids may experience weakness, intermittent pain, fatigue, and nausea – concerns that greatly hinder physical performance.  Incidentally, zinc, B12, calcium, and vitamin D are also essential for proper muscle function. 
6. Bone Health
A study involving 109 men and women for the evaluation of bone health found that vegetarian men reported more bone fractures.  This study shows that a general dietary guideline can't be followed blindly by both sexes, as men may need more calcium, protein, or magnesium than women.
7. Osteoporosis Risk
Homocysteine is an indicator of bone mineral density (BMD), and when levels increase, BMD decreases. This can increase the risk for osteoporosis. One study found that elderly female vegetarians had higher levels of homocysteine and lower bone mineral density than non-vegetarian.  In general, vegetarians have lower bone mineral density, making nutritional planning an integral part of a healthy vegetarian lifestyle. 
8. Getting Enough Vitamin D
Vitamin D plays a role in bone health and supports the immune system, heart health, and cognitive function. Studies that compare vegetarians against omnivores report that meat-abstaining individuals have vitamin D levels that are 30% less.  However, it's also important to note that most people today, vegetarian or not, are deficient in vitamin D.
9. Vegetarian Children and Iron Deficiency
While there are many vegetable sources of iron, it doesn't help if they're not consumed. A Polish study examining children on vegetarian diets found that vegetarian children had lower iron levels than their omnivore contemporaries.  The good news is that vegetarian children exhibited higher vitamin C levels, a nutrient responsible for enhancing iron absorption. Since children require more iron for development, vegetarian diets need careful monitoring in these age groups.
10. Possible Stroke Risk
Although many factors contribute to stroke, homocysteine is high on the list. In one study of stroke victims, over 40% were vegetarians with high homocysteine.  A little over 60% of patients who suffer from high homocysteine suffer a stroke. As we said previously, vitamin B12 may mitigate high homocysteine concerns.
Oddly enough, Leonardo da Vinci is an example of these findings. The artist was reported to have embraced a vegetarian lifestyle during his last five years of life. Apparently, it was also reported that he suffered from weakness along the right side of his body, likely the result of stroke and poorly planned diet. 
Protect Yourself With Knowledge
So does all this mean that a vegan or vegetarian diet is just a series of potential concerns? Not at all! A vegan or vegetarian lifestyle can be a phenomenal way to supercharge your health; however, a balanced diet is absolutely required and it's far more than apples, oranges, and the occasional banana. Avoid deficiencies and imbalanced diets. Before going vegetarian or vegan, educate yourself. Read books, have a list of foods and recipes ready to go, and consider consulting with a dietitian who can steer you clear of common mistakes and pitfalls.
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†Results may vary. Information and statements made are for education purposes and are not intended to replace the advice of your doctor. If you have a severe medical condition or health concern, see your physician.