On the hunt for the market's most reliable stocks? Long-term investors would be hard-pressed to do better than Abbott Laboratories (NYSE:ABT), one of health care's premier blue-chippers and a dividend investor's dream. Abbot might not be the sexiest stock on the market or much of a growth pick, but the stock has gained a solid 5.8% year to date.

However, Abbott's biggest draw over the long term might just be its 2.2% dividend yield. The company's breadth across the health-care sector, its exposure to numerous foreign markets, and its strong history of dividend increases make this yield one of the most reliable around. But can you count on it for the long run?

Nutrition's big opportunity
If Abbott's history is anything to go by, the company is well-suited for future dividend increases. Abbott is one of the S&P 500's vaunted dividend aristocrats, companies that have raised their payouts annually for at least the past 25 consecutive years. Abbott's strong cash flow and manageable 42% dividend payout ratio leave it with plenty of flexibility to continue servicing those annual increases.

But the past isn't always a good predictor of the future, and it'll take ongoing success at Abbott's core businesses to keep this dividend darling flying higher. Abbott may have lost its biggest boom-or-bust division when it spun off its pharmaceuticals operations into AbbVie, but that doesn't mean the company lacks strength in its core businesses.

Abbott's nutritional segment has emerged as its largest business by revenue in the year and a half since the AbbVie split, and there's plenty of long-term optimism in this industry for dividend investors. While the segment posted a 1.7% year-over-year drop in operational sales in Abbott's most recent quarter -- and while currency issues will always be at play in this internationally focused unit -- the company has a great opportunity abroad to capitalize on demographic trends for years to come.

Source: Wikimedia Commons.

It's important to take last quarter's result in perspective: A supplier recall last year hit multiple nutritional powers in China and has led to the ongoing slide in sales for Abbott. Danone (NASDAQOTH:DANOY), another major player in the international nutritionals sphere, took a big hit as well: the company's early life nutrition group saw a 4.8% decline in volume during its most recent quarter due to the recall. In the long run, however, this pressure should ease. Vegetable oil and fat producer AAK saw 19% average annual growth in the Chinese infant nutrition market from 2007 and 2010, and with China's population favoring international suppliers over domestic nutrition makers, Abbott, Danone, and other leaders in this space are primed to extend their dominance in this industry's largest market.

Abbott has plenty of ground to make up in market share in China. The company's 3.1% share lags far behind the nation's leading infant nutrition provider, Mead Johnson (NYSE:MJN), which maintains a 9.2% market share. Mead Johnson's success, though, shows the kind of potential in this industry: The company posted 11% sales growth in Asia last year, with infant formula sales growing 7% worldwide. As long as Abbott can maintain its place among the leaders in the nutritional business, this cash cow's a good bet to continue delivering year after year for the company's dividend.

More than just nutrition
Abbott's diagnostics business has ramped up as the biggest growth driver as of late, even if it's still a much smaller business than nutritionals by revenue. In the company's latest quarter, operational diagnostics sales jumped by more than 5%. Abbott still trails sector heavyweight Roche (NASDAQOTH:RHHBY) in terms of total diagnostics revenue, but Roche's performance shows that this is an industry that can bring in more than enough cash to sustain Abbott's dividend. Roche posted diagnostics sales growth of 4% at a constant currency in 2013 and projects strong growth going forward even as reimbursement rates in the U.S. decline due to health-care reform.

Abbott is fourth in overall market share in this industry, but opportunity abounds. International growth has surged in diagnostics, and the up-and-coming field of personalized medicine has driven expectations higher around the industry in the long run.

By contrast, the company's medical device and generic drug segments certainly aren't the pictures of high-growth businesses, but they're steady cash-generating machines that look rock solid for the long term. Abbott's savvy moves in generics have propelled the company to the top of the market share leaderboard in India, the world's second-largest country by population, and one with a developing middle class. The company also recently purchased Russian drugmaker Veropharm for nearly $500 million, increasing Abbott's reach across the top emerging markets. Add to that Abbott's purchase of Chilean drugmaker CFR Pharmaceuticals for nearly $3 billion earlier this year, and this company's generics business is set to reel in the potential of the world's developing regions.

Abbott's vascular products division, dominated by sales of drug-eluting stents, is the company's smallest by revenue and has taken a hit lately from pricing pressures and tough competition in the device industry. But innovation may be the key to a long-term gain here: Abbott's Absorb bioresorbable stent, which dissolves after use in the bloodstream, already has won approvals in Europe and the U.S. While Abbott is still pushing toward FDA approval, this device could be a game changer in the stent industry -- and one that keeps this medical device unit on an upward track.

Abbott's dividend on pace for long-term success
Abbott Labs took a hit in the first quarter, but in its long-term projections, this company and its reliable dividend look like big winners. The nutritionals and diagnostics markets offer plenty of upside in the long term, particularly within emerging markets -- and that geographical edge lends itself to Abbott's generics cash cow, as well. With a long history of dividend boosts in its past and a steady business model, it's hard to bet against Abbott's dividend in the long run. This is one stock that looks great in any health-care investor's portfolio.