Plant-Based Nutrition

Like most of us, I used to think a plant-based diet was restrictive and extreme, and that vegans were unavoidably unhealthy.  I believed this until the very week I went vegan.  Once I made the decision to stop eating all animal products, I was somehow able to find the evidence all over the place; evidence I simply hadn’t wanted to see before.

The truth is that the leading nutrition experts in the country (Harvard, Cornell, the American Dietetic Association, and many others) agree that 100% plant-based diets can be “healthful, nutritionally adequate, and may provide health benefits in the prevention and treatment of certain diseases.”i

How does one eat a nutritionally adequate plant-based diet?  Thankfully, nutrients (yes, including protein) are abundant in plants and plant-based foods!  It is easy to avoid a vitamin deficiency, because we know the few nutrients we must consider.

Although cereals, dairy products, processed foods and even meat (via supplemented animal feed) are heavily fortified, the typical American diet is STILL often lacking in important nutrients.ii iii iv  It’s not hard to understand why when we learn that 90% of Americans fail to eat enough fruits or vegetables.  If you really think about it, going through the bodies of animals to get the nutrients they got from eating plants is wasteful and unnecessary, when we can simply eat the plants ourselves.

(Note: I am not covering the protein myth in this article.  For more information on protein and veganism, click here.)

Here are the nutrients you may want to consider when eating a plant-based diet:

According to the American Journal of Clinical Nutrition:

“Micronutrients of special concern for the vegan include vitamins B-12 and D, calcium, and long-chain n–3 (omega-3) fatty acids.  Unless vegans regularly consume foods that are fortified with these nutrients, appropriate supplements should be consumed.  In some cases, iron and zinc status of vegans may also be of concern because of the limited bioavailability of these minerals.”vi

Here those are in a handy bullet-point list:

  • Vitamin B-12
  • Vitamin D
  • Calcium
  • Omega 3 fatty acids
  • Possibly iron
  • Possibly zinc

Let’s talk about each of these in more detail.

Vitamin B-12

B12 is sometimes used as “proof” that humans need to eat meat, since it isn’t present in most plant foods.  The reality is that B12 is produced by bacteria that, although not in plants, are abundant in soil.  According to MIT: “Vitamin B12 is produced by soil microbes that live in symbiotic relationships with plant roots.”vii  They are also synthesized by bacteria in our digestive tracts, but the vitamin is produced too far down to be absorbed.viii

B12 is important for red blood cell production and the prevention of anemia.ix Recommended daily dose is between .9 mcg and 2.8 mcg (micrograms) per day depending on age, gender, and pregnancy status.x

You can find this vitamin in fortified cereals, non-dairy milks and nutritional yeast.  There are very affordable sprays and sublingual tablets at the store with dosages in the 500 mcg+ range.  Studies show that about 1% of the B12 you take will be absorbed, so taking a 500 mcg supplement will give you amounts well over the requirement.xi  It is recommended that everyone over age 50 take a B12 supplement, regardless of diet.

Vitamin D

Vitamin D is important to keep our bones healthy, as well as “cell growth, neuromuscular and immune function, and reduction of inflammation.xii  It is produced by our bodies when we are exposed to the sun, but it is particularly difficult (and impossible in some areas) to produce during the winter.  Although vitamin D is often associated with cow’s milk, that is because cow’s milk is fortified with the vitamin.xiii

The recommendation for all ages is between 400 and 800 IUs (International Units) of vitamin D per day, which is 10-20 mg.xiv  While you may make enough of this important vitamin from being in the sun during the warmer months, it’s usually a good idea to supplement vitamin D during the winter, regardless of diet.  A whopping 95% of American adults fail to consume adequate amounts of vitamin D.xv

Vitamin D is derived from vegan and non-vegan sources.   D2 is from vegan sources and most often found in fortified non-dairy milks (almond, soy, coconut).  It is also in mushrooms that have been exposed to ultraviolet light.  In fact, if you place your mushrooms in the sun for an hour in the winter, eating three of them will meet your daily vitamin D requirement!xvi 

There are also breakfast cereals and orange juices that are fortified with vitamin D.  This is often with vitamin D3, which is usually derived from sheep’s wool or fish.xvii Some vegans choose to avoid D3 when it is labeled as such, but the definition of veganism does not require this.xviii At its heart, veganism is not about purity or perfection; it is about trying the best we can for ourselves, the animals, and the planet.

Calcium

Calcium is a fascinating mineral to study in the context of veganism. It is one of the most abundant minerals in the human body and, as you probably know, necessary for bone health.  If you are like most people in America, you have been raised to believe that we need to drink cow’s milk for calcium, and that milk from a cow “does a body good”. The United States daily recommendation for calcium is between 700 and 1300 mg (milligrams) depending on age.xix

Surprisingly though, calcium intakes are much lower in some countries— as low as 300 mg per day in some, such as Japan.  Yet the people there experience fewer fractures.xx Certainly there are other factors to take into account besides the consumption of dairy products, but consider the maps below.

This is a map of hip fracture risk rates worldwide, from Osteoporosis International. Where estimates are available, countries are color coded.  Red means greater than 250 people per 100,000 get a hip fracture each year.  Orange means between 150 and 250 per 100,000 get a hip fracture, and green means fewer than 150 per 100,000 do.xxi  There are about 319 million people in the United States, so that means between about 500,000 and 800,000 people in the U.S. will suffer a hip fracture this year.

Hip Fractures

Now, compare this to a map of global consumption of cow’s milk, based on statistics from the Food and Agriculture Organization of the United Nations.xxii  Notice any similarities?

Milk Consumpton

According to Harvard Health:

“…Studies suggest that high calcium intake doesn’t actually appear to lower a person’s risk for osteoporosis. For example, in the large Harvard studies of male health professionals and female nurses, individuals who drank one glass of milk (or less) per week were at no greater risk of breaking a hip or forearm than were those who drank two or more glasses per week. When researchers combined the data from the Harvard studies with other large prospective studies, they still found no association between calcium intake and fracture risk.”xxiii (Emphasis added)

Harvard even has their own version of the USDA’s MyPlate guide based on their nutrition research Harvard points out that “Intense lobbying efforts from a variety of food industries also helped shape the pyramid and the plate” that the USDA issued, hence the need for an independent guide based on research. In Harvard’s Healthy Eating Plate, dairy is only mentioned as being something you should “limit”.xxiv

Heathly Eating Plate

So it turns out the “milk life” may not be so healthy after all and “milk truth” is not at all what you see in advertisements.  In fact, according to a study published in the British Medical Journal, milk may be much more harmful than we think: “Milk is the main dietary source of D-galactose…Even a low dose of D-galactose induces changes that resemble natural aging in animals, including shortened life span caused by oxidative stress damage, chronic inflammation, neurodegeneration, decreased immune response, and gene transcriptional changes.” For the milk drinkers in the study, risk of osteoporosis, cardiovascular disease, and cancer were all found to be higher.xxv

Calcium is still important, but the best source for humans is not bovine milk.  Vegans have been shown in some studies to have a higher fracture risk than non-vegans.  Although it is possible that is due to other factors (lack of vitamin D, or weight-bearing exercise, for example), vegans, like everyone else, should be aware of their calcium intake.xxvi  In fact, 50 % of all Americans fail to reach the recommended daily allowance of calcium.  So, as with most of the nutrients in this essay, these are important considerations regardless of diet.  One study indicated that vegans who consumed at least 525 mg of calcium per day had a fracture risk similar to other diets.xxvii

Calcium supplements are not recommended due to a “possible association with cardiovascular disease and an increased risk of kidney stones.”xxviii  Good sources of calcium include fortified non-dairy milks, collard greens, kale, broccoli, fortified cereals, and some tofu.xxix

Omega-3 Fatty Acids

According to Harvard, omega-3s are important because they: “Have been shown to help prevent heart disease and stroke, may help control lupus, eczema, and rheumatoid arthritis, and may play protective roles in cancer and other conditions.”  Sounds pretty important to me.

There are three kinds of omega-3s fatty acids:

  • Alpha-linolenic acid (ALA)
  • Docosahexaenoic acid (DHA)
  • Eicosapentaenoic acid (EPA)

The human body can convert ALA from plants into EPA and DHA, but from what we understand the conversion rates are not great.xxx  In addition to eating foods high in ALA (which we all definitely need), it is a good idea to supplement with DHA and EPA to make sure our bodies have enough of these important fatty acids.  Many vegans meet their needs through ALA consumption only though, and more research is needed.

The good news is that unlike we are often told, we can easily obtain all three of these important fatty acids from vegan sources.xxxi  ALA is present in all sorts of plant foods, and is found in especially high amounts in flaxseeds and flaxseed oil, walnuts and walnut oil, chia seeds, and canola oil.  DHA and EPA are both found in algae, which is where the fish obtain their omega-3s. 

Happily, there are now many vegan DHA and EPA supplements on the market.  Obtaining them from algae supplements is an obvious solution, particularly considering consuming fish and fish oils comes with so many negatives.  These include, among other downsides, increased exposure to lead and other heavy metals, the truly disgusting reality of fish farms, and the environmental impact of severe over-fishing.xxxii 

Iron

The mineral iron is a component of hemoglobin in red blood cells, which move oxygen molecules from our lungs to other parts of the body.  A lack of iron causes fatigue, cold hands and feet, and other symptoms.  Iron Deficiency Anemia is the most common nutritional deficiency in the United States, affecting around 10% of the female population.xxxiii

Unless you are pregnant or a baby you need between 7 and 18 mg, depending on age and gender.xxxiv  Heme iron, the type of iron that makes up 30-60% of the iron content of meat, is more easily absorbed by the body.  However, heme iron only accounts for 10-15% of the total iron consumption in typical Western diets.  That means most of the iron we consume is already non-heme, regardless of diet.  Even beyond that, “In the United States, about half of dietary iron comes from bread, cereal, and other grain products.”xxxv

A simple way to make sure you absorb more iron is to eat iron-rich plant foods along with something high in Vitamin C: studies have shown over and over that eating foods rich in vitamin C with foods that contain iron significantly increases the body’s absorption of the iron.xxxvi

Good sources of iron include all kinds of legumes, whole grains, dark leafy greens, nuts, seeds, and even dried fruit.xxxvii  Eat your whole-wheat pasta with red sauce, drink orange juice with your bean burrito, or have broccoli with your lentils and rice to increase absorption.

Zinc

Zinc is a mineral which is essential in the action of around 100 enzymes throughout the body.  It is also important for normal cell division and immune function, along with the construction of DNA and proteins.

Zinc is of special concern to vegetarians and vegans because phytates (antioxidants) in some plant foods attach themselves to zinc molecules, theoretically reducing the amount available to absorb.  Because of this, it may be a good idea to increase your daily zinc intake to about 50% above the recommended levels, but keep in mind that zinc deficiency is uncommon in the United States.xxxviii  Interestingly, milk protein (casein, abundant in all dairy products but concentrated in cheese) also inhibits the absorption of zinc.xxxix

Despite the bioavailability concerns mentioned above, legumes, spinach, chives, and peppers (among other plant foods) contain high levels of certain amino acids that actually appear to increase zinc absorption.xl You can also increase zinc’s bioavailability by soaking or even sprouting legumes, whole grains, and seeds before cooking them, as well as by eating leavened whole grain breads. Both of these methods break down the phytates in these foods, keeping them from binding with the zinc.xli

Our bodies don’t store zinc, so it is important to consume some every day.  We require between 2 and 13 mg per day, depending on age, gender, and pregnancy status.xlii

Plant foods high in zinc include legumes, whole grains (including wheat, oats, and others), nuts, cereals and soy products.xliii

My experience

In my experience, getting all the vitamins and minerals you need is EASY on a vegan diet.  My iron levels actually increased (without supplements) when I went vegan.  Nowadays, I drink almond milk daily for calcium, eat lots of fruits, vegetables, beans, nuts and whole grains, take a multivitamin and algae-based DHA/EPA.  It’s really that simple.

As someone who was vegetarian for over two decades before going vegan, I am healthier now in my mid-thirties than I have ever been.  When I get sick it lasts about a day, my allergies are better, my asthma is better, and I don’t have to diet to control my weight.  

And beyond all the nutrition in the world, there is a unique feeling of peace and lightness that comes with this lifestyleWe are able to live healthy lives and obtain all the nutrients we need while being easy on the earth, our bodies, and the bodies of animals.  It’s a gift we should not take for granted.

Thank you for reading!

Important Note:

Always talk to a nutritionist or Registered Dietitian before making any changes.  Or a doctor, but keep in mind that medical doctors get very little training in nutrition.  All information on this website is for informational purposes only, based on what I’ve learned through my research. This site does not provide medical advice and is not written by a medical or nutrition professional.

For Further Reading

http://www.theveganrd.com/

http://news.mit.edu/2007/b12

http://www.ncbi.nlm.nih.gov/pubmed/9637947

https://ods.od.nih.gov/factsheets/Calcium-HealthProfessional/

http://www.hsph.harvard.edu/nutritionsource/calcium-full-story/

http://www.health.harvard.edu/staying-healthy/becoming-a-vegetarian

http://www.eatright.org/resource/food/vitamins-and-supplements/dietary-supplements/vitamins-minerals-and-supplements

https://www.nlm.nih.gov/medlineplus/vegetariandiet.html

http://www.nutrition.gov/smart-nutrition-101/healthy-eating/eating-vegetarian

https://www.brown.edu/campus-life/health/services/promotion/nutrition-eating-concerns-eating-well-brown/being-vegetarian

References

 

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