There is tons of vegan nutrition information on the internet and a whole lot of it stands on pretty shaky ground. Last month I read an article—written for vegans—about tree nuts and their effects on health. The writer built what seemed like a rock solid case against consuming nuts by:

  • referencing some outdated science
  • misrepresenting the findings from one recent study, and
  • blatantly ignoring the rather impressive number of studies that have linked nuts to protection against chronic disease.

The article had references and sounded authoritative and convincing—but it wasn’t even close to being a balanced perspective on the topic.

The volume of data on any particular topic is enormous. For example, when I went into Pub Med (the database of published research articles) I found well over 2,000 studies on dietary aspects of nuts. It’s a safe bet that no matter what I wanted to say about nuts and health, I could find a study or two to support it.

That’s because there are very few issues in nutrition where all of the studies are in agreement. Even where most of the research shows more or less the same thing, there will always be a few outliers—a few studies that, for whatever reason, come up with different results. So it’s easy to make any case you would like in nutrition by “selectively citing” the research. That is, choose the studies that support your theory and ignore the rest.

As a result, it’s a waste of time to engage in “dueling study” debates. Nutrition theories are not built on a handful of studies, they are built on an analysis of all the research on a particular topic. And even then it can be difficult to draw solid conclusions.

There are, of course, some things we can say about nutrition with certainty. For example, if you don’t have any vitamin C in your diet, it’s a safe bet that you’ll get scurvy and die. And, we have good evidence to suggest that diets containing lots of whole plant foods are beneficial. But when it comes to the details of eating for optimal health—beyond simply meeting nutrient needs—it’s a whole lot harder to be certain about recommendations.

And that’s a problem, because most people who want to improve their health would like clear-cut advice about how to do it. Nobody wants to hear that most nutrition advice is not much more than a bunch of educated guesses. That’s why popular diet gurus and bestselling authors are almost always very authoritative-sounding and confidently exact in their recommendations.

With so many different perspectives on these topics, it isn’t easy to know who or what you should believe. There are no foolproof ways to decide whether a resource or person is reliable, but it can help to ask a few questions:

  • Does this person promote one very precise eating pattern as the only healthful way to eat? The scientific literature is far too complex—and conflicting—at this point for anyone to know all the details of the one and only way to eat for good health. There is good evidence showing that a vegan diet is more healthful than the usual American eating pattern–but the science doesn’t support the idea that it’s the only or most healthful way to eat.

  • Is the information all or nothing? From an ethical perspective, I’m pretty comfortable saying that meat, eggs and dairy should never be consumed. But it’s harder to make those 100 percent kinds of recommendations from a scientific standpoint. Likewise, we can say that people should minimize their intakes of refined foods, oils, sugar and caffeine—but there is no reason to believe that any single food is so bad that it should never be consumed.

  • Is this person saying exactly what he or she was saying 10 or even 20 years ago? Big red flag! People talk about the fact that we nutritionists are always changing our minds. One day something is good for you and the next day it’s bad. It’s frustrating but the research is ever evolving and responsible nutritionists have to constantly reassess what we believe to be true. I give very different advice about vegan diets today than I did a decade or so ago. Anyone who doesn’t is not critically evaluating the nutrition research.

The easiest way to make sure you are getting solid and dependable information about vegan diets is to stick with sources that are well-regarded among vegan nutritionists. I highly recommend these two:

VeganHealth: This site, associated with Vegan Outreach, is constantly updated by Jack Norris, R.D. and, it is packed with information. (I would also recommend taking a look at his discussion of the different types of studies used in nutrition research for a better understanding of why all research findings are not considered to be equally important.)

Vegetarian Resource Group: Most of their nutrition material is written by Dr. Reed Mangels, RD and Dr. Suzanne Havala-Hobbs, R.D. and it’s always reliable. There is lots of practical advice here for families. Look at the nutrition part of their website and also be sure to read the Nutrition Hotline and Scientific Update sections of their Vegetarian Journal online.

You can’t go wrong in using these resources to guide your food choices, and they are pretty much the only online information sources you need. And if you appreciate the availability of good vegan nutrition information, you can support these efforts by donating to Vegan Outreach and Vegetarian Resource Group.