https://www.californiaavocado.com/blog/march-2016/is-it-safe-to-eat-the-avocado-seed

We have received a lot of questions from consumers and dietitians lately asking us what we think about consuming the avocado seed/pit. So is it safe to eat the avocado seed? We don't recommend it.

While this is presently a very popular topic and there is a body of evidence looking at extracts of the avocado seed, the fact is there is not enough research to support consuming an avocado seed. The purported health benefits and risks of avocado seed intake are poorly characterized. 

As stated in a 2013 research study by Pennsylvania State University, “although the currently available data is promising, for most indications, it remains very preliminary and further studies are needed” and “In addition, the safety of the various extracts of the avocado seeds must be assessed in order to more fully estimate the usefulness of this resource."

While it is not recommended that you eat the seed of the avocado, the fruit/pulp of the California Avocados is ripe with nutrition. One-fifth of a medium avocado (1 oz.) has 50 calories and contributes nearly 20 vitamins and minerals, making it a tasty choice for a nutritious and healthy diet. California Avocados are naturally sodium and cholesterol-free; a naturally nutritious superfood. 

And some research papers to chew on:

Avocado (Persea americana) seed as a source of bioactive phytochemicals

http://www.researchgate.net/publication/235755293

Nutritional efficacy of avocado seeds

https://www.researchgate.net/publication/282104753

Optimization of the antioxidant and antimicrobial response of the combined effect of nisin and avocado byproducts

http://dx.doi.org/10.1016/j.lwt.2015.07.048