One of the most delightful moments during the longevity-focused conference I attended last month came in between speakers, when I was wandering around the booths with Annee de Mamiel. I heard a bright, “DARA!” and turned around to see my friend Ning.
Ning was my classmate at Princeton; I ran into her around town occasionally while I was at Harvard Business School, too, since she attended Harvard Medical School at the same time. Ning had been my sorority sister while at Princeton and a frequent witness to my exuberant love of fun parties with bubbly drinks, so whenever I see her, I detect a sense of glee along with a dash of surprise that somehow I ended up OK. (Maybe I’m imagining the surprise. The glee is always nice to see, in any case.)
Ning has an awe-inspiring resume: after her residency at Massachusetts General Hospital, she spent five years as an internal medicine physician and assistant clinical professor of medicine at UCSF, then another five years as a clinical associate professor of medicine at Stanford University, where she was also a senior medical director at Stanford Health Care. She is one solidly smart cookie and has always done all the homework, digging up every detail. These types of people are very good to know.
But you know what I extra love about her? Ning now works on her own as an integrative medicine physician, where she blends evidence-based conventional medicine with functional medicine, mind-body medicine, nutrition science, lifestyle medicine, and genomics. It’s pretty rare to see someone with credentials like hers dive into the world of integrative and functional medicine. And it’s exciting! So, when we were catching up and she mentioned her recent digging into the world of supplements and described her work as “kind of like being a medical detective,” my eyes grew very large; she laughed and said, “We should chat,” and I, of course, jumped all over the opportunity.
Our first topic of conversation: the fundamentals. Do we even need supplements, or am I crazy for being so smitten with them? In a world where influencers are sharing their stacks of 20 or 30 supplements, how do you actually know what you need? Ning will tell us why even people who eat beautifully often need supplementation today, what kind of doctor to look for if you want guidance, and the simple safety principles she walks every patient through before recommending anything. It’s an excellent Supplements 101.
This part of the conversation covers:
Why food alone often isn’t enough anymore
The unregulated reality of the supplement industry and what to look for in a brand
Why she doesn’t recommend buying supplements from Costco or Amazon
How to find a physician who actually understands supplementation
The difference between integrative medicine and functional medicine, and what to look for
The four blood values she always monitors when patients are on supplements
For those of you who like reading ahead: next week, juicy Part Two will cover microbiome, blood, and salivary testing; gut health and inflammation; food sensitivities; mitochondrial support; advanced cardiovascular markers; and how to think about supplements alongside (or instead of) prescription drugs.
Juicy indeed! But let’s enjoy the present.
Q: Do we all need supplements? Shouldn’t a healthy diet be enough?
Dr. Tang:
Many—if not most—of us do need supplements. Vitamin D is a good example. I was a primary care physician at UCSF for five years, and then at Stanford for another five, and I was shocked to see how many of my patients had low vitamin D levels. Even on the peninsula, where there’s more sun than in San Francisco, most of my patients were deficient. So I put most of them on a vitamin D supplement.
But “shouldn’t a healthy diet be enough?” That’s what I was taught in medical school: if your patients eat a healthy, balanced diet, supplements aren’t necessary. But what we don’t take into account is the quality of our food sources today compared to fifty years ago. Farming has changed dramatically. Back then, farms were primarily small family farms where crops were rotated and the soil was dense with nutrients. Farmers weren’t using anywhere near the amount of pesticides and chemicals that they use today. Now we have large commercial farms that follow practices to maximize output, which often means over-farming and a lack of crop rotation, and that depletes the soil. As a result, fruits and vegetables are not as dense in vitamins and minerals as they used to be.
Me: Just fifty years—that’s not that long.
Dr. Tang: No. We could all be eating salads every day for lunch, packing in as many greens as we can, and it’s still just not as nutrient-dense as we’d like.
Me: So if leafy greens aren’t as nutrient-dense as they used to be, is the answer something like a greens powder?
Dr. Tang:
I don’t go that far. I still encourage all of my patients to shop the perimeter of the grocery store, buy fresh, ideally organic produce, and even better, buy from a farmer’s market. Eat the broccoli, the cauliflower, the brussels sprouts, the dark leafy greens. Eat the colors of the rainbow. What I’d say is consider doing some micronutrient testing, because we may still be deficient in certain vitamins and minerals that we want to supplement. But for our gut microbiome — and to reduce potential toxins — I still believe it’s much better to eat foods as they occur in nature than to take a greens powder.
There’s a manufacturing process that goes into any powder. Some companies have more transparency than others. Some follow safer manufacturing processes that reduce exposure to heavy metals and other toxins. Some have third-party testing to confirm that the dose of every vitamin and mineral advertised is actually in the product. Every company is different in how they follow each of those guidelines, and it’s really hard for consumers to know where each one places its values.
Q: How should we think about incorporating supplements into a daily routine?
Dr. Tang:
For most people, supplements are a good idea, but most people do not need to go overboard. There are health practitioners out there who recommend twenty, thirty, or forty supplements. None of my patients are on that many. I largely determine which supplements a patient needs based on their testing—blood, stool, saliva, and urine—and the recommendations are very much targeted to that individual.
I would take supplements under the guidance of a trained physician; I’d lean toward someone who actually understands supplementation. Make sure your physician checks for prescription drug-supplement interactions and supplement-supplement interactions, which exist; that they understand supplement side effects and warnings, which exist; and that they monitor key blood chemistries while you’re on supplements.
The two key sets of blood chemistries to follow are liver function (AST and ALT) and kidney function (creatinine and estimated GFR). Ideally your physician obtains baseline values for these four blood tests before you start a supplement and then again within a month of starting it, just to make sure there aren’t any bumps. Supplements and prescription drugs are cleared by either the kidney or the liver, so we want to follow those numbers for safety.
Q: How do you find a doctor who can actually guide you on supplements?
Me: If you were taught in medical school that a healthy diet should be enough, how does someone find a doctor who is open to working on supplement choices, rather than one who’ll just say you don’t need any of that?
Dr. Tang:
Look for a physician with training in integrative medicine. There are now fellowships and additional training programs for physicians who are interested in more than what Western medicine alone offers. Physicians with integrative medicine training generally understand supplements more and may even have specific education around them. So I’d look for integrative medicine training or board certification.
Look at where they trained and at their years of experience after completing their training program(s). Definitely aim for five or more years; ten or more is even better.
Q: What’s the difference between integrative medicine and functional medicine?
Dr. Tang:
Integrative medicine can be a catch-all phrase for a physician who combines conventional Western medicine with other forms of healing. It could be Eastern medicine—acupuncture or Ayurvedic medicine. It could be more naturopathic medicine, focused on herbs and botanicals. It could be a focus on nutrition and lifestyle. It could incorporate more spiritual, mind-body medicine. There isn’t one definition for integrative medicine.
Functional medicine, if we strip away who is practicing it, is a way of looking at medicine that is systems-based—it recognizes the interconnectedness of each organ system in the human body. It’s root-cause medicine. You can’t look at the heart in isolation without understanding inflammation everywhere else in the body. You can’t look at brain health without understanding that there’s a gut-brain axis, and if you don’t address gut health first, you’re never going to get to the root cause of the brain symptoms. Functional medicine is always peeling back the layers to understand what’s driving the symptoms and asking whether addressing the root cause can essentially resolve the symptoms—rather than placing band-aid solutions that merely mask symptoms.
I love functional medicine for that reason. The challenge is that there’s a wide variety of people practicing it. There are amazingly talented practitioners, especially here in the Bay Area—we’re fortunate to have access to them, and I would not hesitate to send my friends and family to them. But you do have to be careful about who you choose to work with. So when patients ask me how to evaluate someone, I tell them to look for an MD or a DO. Look for any mention of integrative or functional medicine training in their bio. Look for some indication that they actually work with supplements in their practice. And look at their training and their years of experience.
Q: Why does it matter so much where you buy supplements?
Dr. Tang:
When I was a primary care doctor at UCSF, I had many patients who would bring in supplements they bought from Costco and ask if it was okay to take them. Usually I’d say yes—some extra vitamin C, some extra vitamin A, fine—until I’d draw their blood tests and find that their liver enzymes were elevated. I’d go through the usual list of what can cause elevated liver enzymes, like alcohol, hepatitis, fatty liver. Nothing turned up. So finally I’d take them off the supplements they’d bought from Costco—and lo and behold, when we rechecked the liver tests, the results were normal.
The supplement industry is not regulated by the FDA the way prescription drugs are. There are no regulations around manufacturing, and toxins, including heavy metals, have been found in third-party tests—toxins that damage the liver and kidneys. There are also no regulations around truthful advertising, and third-party tests often find lower levels of active ingredients than what is advertised. Because the industry is unregulated, anyone who wants to sell supplements can sell them, and they can store them however they want, including not following manufacturer instructions on temperature control.
For my patients, I only recommend supplements from manufacturers that have undergone third-party testing for purity and safe manufacturing practices. I love Costco for so many reasons, but not for supplements. There are a lot of good supplement companies; I’ll list a few—and it doesn’t mean a supplement is bad if it’s not on this list—but I like Metagenics, Thorne, Integrative Therapeutics, Pure Encapsulations, Klaire Labs, and Nordic Naturals. They have a good reputation for being clean, advertising their effective dose accurately, and being third-party tested.
I also encourage my patients to buy from retailers with safe storage and handling, especially temperature control. I do not use Amazon for supplements. I strongly discourage my patients from using Amazon—there are counterfeit supplements on the platform, and there’s no quality control over storage conditions. Amazon is convenient, the two-day shipping is amazing, but I would not buy supplements or food products there.
Q: What other general guidelines should everyone keep in mind?
Dr. Tang:
Take supplements as directed. So many people think of supplements as healthy by definition: “If a little is good, more must be better.” I encourage my patients to think of supplements the way they’d think about prescription drugs and only take them as directed. There are supplements that, if you take too much, can cause real damage. Some can cause nerve damage—numbness and tingling in the fingers and toes—and the symptoms don’t resolve until we wind back the dose. Vitamin D is another good example. So many people in San Francisco and the greater Bay Area are deficient, but if you overdose on vitamin D, it can cause serious kidney damage. So I’d never want to overdose any of my patients on it. Vitamin D is one of those tests I repeat several times a year to make sure we’re on the right dose—not too little, not too much.
The other thing to consider is interactions between the supplements you’re already taking. I just spent five hours this afternoon—not joking—reviewing a friend’s supplements. She sent me her list and asked whether anything was redundant, whether she was taking too much of any one ingredient, or missing anything. I reviewed all of her lab results, matched her lab values for various minerals and vitamins against her supplement list, and looked at the ingredients of every supplement to see if there was overlap. What I found was that, taken together, she was getting way too much vitamin B6, folate, and B12, as well as zinc. If you take too much zinc, your copper levels can drop too low—you need the right balance of zinc and copper. So when many of your supplements have ten or more ingredients, you can easily end up with too much of a specific micronutrient without realizing it. You have to be careful of that, too.
Coming next week
In part two of our conversation, Dr. Tang gets into the testing-driven approach that she recommends: what tests she uses to actually personalize a supplement plan, why she starts almost every inflammatory case by looking at the gut, how she thinks about mitochondrial health and longevity, the surprising ways food sensitivities show up in our bodies, and what she looks for in older patients that standard cholesterol panels miss.
Subscribe to be the first to read it, and paid subscribers get an extra benefit: ask any question you’d like Ning to answer in the comments. I’ll see what I can do!
And if you’re thinking, “Forget the comments, I just want to see Ning myself,” you can find out how to do that here.
A note on this conversation: This interview is intended for educational and informational purposes only. It is not medical advice, and it is not intended to substitute for the advice of your physician or other qualified healthcare provider. Always consult your own doctor before starting, stopping, or changing any supplement or medication, particularly if you are pregnant, nursing, taking prescription drugs, or managing a medical condition.
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