If you want to maximize your Roth IRA, don't overlook these three stocks. Image source: Author.

If you have a Roth IRA (or are planning to open one soon), then you probably know how amazing of an investment tool it is, allowing you to build up a source of tax-free wealth and income for retirement. 

It's also important to make the best investing decisions to take best advantage of that wealth-creation. We reached out to three regular contributors and asked them, "What is one stock that people overlook for their Roth IRA?" They gave us three companies from very different business, but each has some interesting characteristics that makes it compelling. Here's what they had to tell us. 

Years of growth ahead
Tim Green: For investors with decades left until retirement, Roth IRAs are perfect for stocks with plenty of long-term growth potential. Paying capital gains taxes on holdings that have appreciated by hundreds, or even thousands, of percentage points over many years is no fun, making a Roth IRA a good choice to hold attractive growth stocks. Whole Foods Market (WFM) is a great example.

The upscale grocer has been going through a bit of a rough patch lately, and its stock has tumbled more than 45% over the past year. Comparable-store sales have been falling, driven in part by an overcharging incident last year, but also by increasing competition in the natural foods space, particularly from traditional supermarkets. Going forward, there's a chance that Whole Foods will see its margins permanently contract as competition heats up.

But despite these challenges, Whole Foods still has plenty of growth ahead of it. The company operates about 400 stores, with a long-term goal of tripling that number to 1,200. On top of this growth, Whole Foods' value-oriented 365 by Whole Foods Market stores, slated to begin rolling out this year, offers the company an opportunity to go after more value-conscious consumers who have shunned the company's "Whole Paycheck" image thus far.

A lot can still go wrong for Whole Foods, but with the stock trading at the lowest level relative to earnings since the financial crisis, tossing some shares into a Roth IRA isn't a bad idea.

Healthcare or real estate? Both
Matt DiLallo: Investors often overlook that some stocks are better suited than others for a Roth IRA. Real estate investment trusts, or REITs, top that list because the generous dividends they pay can compound tax free in that account. Even better, that income is never taxed when you do retire.

While there are a lot of REITs out there, one of my favorites is Medical Properties Trust (MPW -8.32%), which is a company that primarily invests in hospitals. Currently, the company owns just under 200 properties across 29 states and in five European countries. The reason it has chosen to invest almost exclusively in hospitals is that they provide steady and reliable income because of their being such an important part of a community's healthcare infrastructure.

Over the past three years, Medical Properties Trust has doubled its asset base by making smart hospital acquisitions as well as providing financing for the buildout of healthcare real estate. However, the company has financed this growth very prudently and has actually grown into an investment-grade credit rating by reducing its single-tenant concentration while not growing its dividend as fast as its cash flow in order to strengthen its payout ratio. That said, despite paying out only two-thirds of its cash flow, Medical Properties Trust yields a whopping 8.8%. So not only is the income very generous, but it's also rock-solid for the long term, making it a stock you don't want to overlook for your Roth IRA. 

Income and value in the energy sector
Jason Hall: ONEOK (OKE 1.06%) has been caught up in the oil and gas beatdown over the past year, as its gathering business suffered because of commodity price exposure. But the company has largely addressed those issues with new fee-based contracts that provide solid and predictable cash flows. Furthermore, the company recently reached a finance deal that will cover the company's capital growth plans for the next year-plus. 

In short, the risks of investing in this natural gas pipeline company have been largely addressed, but the stock is still cheap. Furthermore, unlike most midstream investments, ONEOK isn't a master limited partnership, which can sometimes create taxable income even inside a Roth IRA. 

ONEOK isn't risk-free but is probably much safer than the market thinks it is right now. Furthermore, the dividend yield is more than 12% on a forward basis today, making it one of the highest relatively secure payouts you'll find. Most important for IRA investors, ONEOK's core business, natural gas and NGL gathering and pipelines, is on track to grow substantially for years to come. 

Combined, that makes ONEOK a great investment choice for a Roth IRA.