Will pages irrelevant to a site's core content dilute SEO value of core pages?

[ArchMedia]

We have a website with around 40 product pages. We also have around 300 pages with individual ingredients used for the products and on top of that we have some 400 pages of individual retailers which stock the products.

Ingredient pages have same basic short info about the ingredients and the retail pages just have the retailer name, adress and content details.

Question is, should I add noindex to all the ingredient and or retailer pages so that the focus is entirely on the product pages?

Thanks for you help!

[MoosaHemani]

I don’t think this will be a good approach… I don’t see these pages are completely irrelevant! But my recommendation is to engage it properly with product pages and if possible get some good links on them instead of including no-index on the pages…

[AdamThompson]

Pages about the ingredients aren't irrelevant. On the contrary, they could be good content pages that could attract users, social shares, and backlinks!

[ArchMedia]

Thanks for your comments!

Agree that ingredient page could be great, with valuable content, but at the moment we just display the name and their role in the product. If I understand correctly google will find hundreds of these pages with pretty much similar content and, at least at the moment, no or few webpages linking to them. This would give this pages a low PR does dragging down the overall PR of the site thus ranking all pages lower.

My assumption is that the PR of a site with 40 valuable content pages, with a lot of inbound links, get dragged down if the site has many more less valuable pages with virtually no inbound links.

I am considering adding some criteria to ingredient and retailer templates to only make them indexable if they contain more than just the basic fields.